Fix paddle docs (#2592)

* fix___init_bug

* fix migration guide

* add api_reference test=develop

* fix style test=develop

* change faq to chinese test=develop

* add release note en

* fix release note test=develop

* fix api_reference test=develop

* fix style test=develop

doc/paddle/api/alias_api_mapping

@@ -44,7 +44,7 @@ paddle.tensor.manipulation.reshape	paddle.reshape,paddle.tensor.reshape
 paddle.fluid.layers.increment	paddle.increment,paddle.tensor.increment,paddle.tensor.math.increment
 paddle.fluid.compiler.CompiledProgram	paddle.static.CompiledProgram
 paddle.tensor.manipulation.flip	paddle.flip,paddle.reverse,paddle.tensor.flip,paddle.tensor.reverse
-paddle.distributed.__init__.paddle.fluid.dygraph.parallel.ParallelEnv	paddle.distributed.ParallelEnv
+paddle.fluid.dygraph.parallel.ParallelEnv	paddle.distributed.ParallelEnv
 paddle.fluid.layers.hash	paddle.nn.functional.hash,paddle.nn.functional.lod.hash
 paddle.nn.functional.activation.selu	paddle.nn.functional.selu
 paddle.nn.functional.input.embedding	paddle.nn.functional.embedding
@@ -193,7 +193,7 @@ paddle.nn.layer.conv.Conv1d	paddle.nn.Conv1d,paddle.nn.layer.Conv1d
 paddle.fluid.param_attr.ParamAttr	paddle.ParamAttr,paddle.framework.ParamAttr
 paddle.fluid.layers.retinanet_target_assign	paddle.nn.functional.retinanet_target_assign,paddle.nn.functional.vision.retinanet_target_assign
 paddle.fluid.initializer.Xavier	paddle.nn.initializer.Xavier
-paddle.distributed.__init__.paddle.fluid.dygraph.parallel.prepare_context	paddle.distributed.prepare_context
+paddle.fluid.dygraph.parallel.prepare_context	paddle.distributed.prepare_context
 paddle.tensor.math.pow	paddle.pow,paddle.tensor.pow
 paddle.fluid.layers.bipartite_match	paddle.nn.functional.bipartite_match,paddle.nn.functional.vision.bipartite_match
 paddle.fluid.input.embedding	paddle.static.nn.embedding
@@ -253,7 +253,7 @@ paddle.tensor.linalg.matmul	paddle.matmul,paddle.tensor.matmul
 paddle.fluid.layers.generate_proposals	paddle.nn.functional.generate_proposals,paddle.nn.functional.vision.generate_proposals
 paddle.nn.layer.loss.SmoothL1Loss	paddle.nn.SmoothL1Loss,paddle.nn.layer.SmoothL1Loss
 paddle.fluid.dygraph.checkpoint.save_dygraph	paddle.save,paddle.framework.save
-paddle.framework.__init__.paddle.fluid.core	paddle.framework.core
+paddle.fluid.core	paddle.framework.core
 paddle.nn.functional.vision.grid_sample	paddle.nn.functional.grid_sample
 paddle.tensor.random.rand	paddle.rand,paddle.tensor.rand
 paddle.fluid.layers.cond	paddle.nn.cond,paddle.nn.control_flow.cond

doc/paddle/api/index_cn.rst

 ==================
-API REFERENCE
+API 文档
 ==================
+
+PaddlePaddle (PArallel Distributed Deep LEarning)是一个易用、高效、灵活、可扩展的深度学习框架。
+本页列出了PaddlePaddle 2.0-beta所支持的API，您可以在此查看该API的相关信息。
+
+此外，您可参考PaddlePaddle的 `GitHub <https://github.com/PaddlePaddle/Paddle>`_ 了解详情，也可阅读 `版本说明 <../release_note_cn.html>`_ 了解新版本的特性。
+
+**飞桨框架2.0的API目录结构如下：**
+
++-------------------------------+-------------------------------------------------------+
+| 目录                          | 功能和包含的API                                       |
++===============================+=======================================================+
+| paddle.\*                     | paddle                                                |
+|                               | 根目录下保留了常用API的别名，当前包括：paddle.tensor, |
+|                               | paddle.framework目录下的所有API                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.tensor                 | 跟tensor操作相关的API，比如：创建zeros,               |
+|                               | 矩阵运算matmul, 变换concat, 计算add, 查找argmax等     |
++-------------------------------+-------------------------------------------------------+
+| paddle.nn                     | 跟组网相关的API，比如：Linear,                        |
+|                               | Conv2d，损失函数，卷积，LSTM等，激活函数等            |
++-------------------------------+-------------------------------------------------------+
+| paddle.static.nn              | 静态图下组网专用A                                     |
+|                               | PI，比如：输入占位符data/Input，控制流while_loop/cond |
++-------------------------------+-------------------------------------------------------+
+| paddle.static                 | 静态图下基础框架相关API，比如：Variable, Program,     |
+|                               | Executor等                                            |
++-------------------------------+-------------------------------------------------------+
+| paddle.framework              | 框架通用API和imprerative模式的API，比如：to_tensor,   |
+|                               | prepare_context等                                     |
++-------------------------------+-------------------------------------------------------+
+| paddle.optimizer              | 优化算法相关API，比如：SGD，Adagrad, Adam等           |
+|                               |                                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.optimizer.lr_scheduler | 学习率衰减相关API                                     |
+|                               |                                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.metric                 | 评估指标计算相关的API，比如：accuracy, auc等          |
+|                               |                                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.io                     | 数据输入输出相关API，比如：save, load, Dataset,       |
+|                               | DataLoader等                                          |
++-------------------------------+-------------------------------------------------------+
+| paddle.device                 | 设备管理相关API，比如：CPUPlace， CUDAPlace等         |
+|                               |                                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.distributed            | 分布式相关基础API                                     |
+|                               |                                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.distributed.fleet      | 分布式相关高层API                                     |
+|                               |                                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.vision                 | 视觉领域API，                                         |
+|                               | 比如，数据集，数据处理，常用基础网络结构，比如resnet  |
++-------------------------------+-------------------------------------------------------+
+| paddle.text                   | NLP领域API,                                           |
+|                               | 比如，数据集，数据处理，常用网络结构，比如transformer |
++-------------------------------+-------------------------------------------------------+

doc/paddle/api/index_en.rst

 ==================
-API REFERENCE
+API Reference
 ==================
+
+PaddlePaddle (PArallel Distributed Deep LEarning) is an efficient, flexible, and extensible deep learning framework.
+This page lists the APIs supported by PaddlePaddle 2.0-beta. You can view the information of the APIs here.
+
+In addition, you can refer to PaddlePaddle's `GitHub <https://github.com/PaddlePaddle/Paddle>`_ for details, or read `Release Notes <../release_note_en.html>`_ to learn about the features of the new version.
+
+**The API directory structure of PaddlePaddle 2.0-beta is as follows:**
+
++-------------------------------+-------------------------------------------------------+
+| Directory                     | Functions and Included APIs                           |
++===============================+=======================================================+
+| paddle.*                      | The aliases of commonly used APIs are reserved in the |
+|                               | paddle root directory, which currently include all    |
+|                               | the APIs in the paddle.tensor and paddle.framework    |
+|                               | directories                                           |
++-------------------------------+-------------------------------------------------------+
+| paddle.tensor                 | APIs related to tensor operations such as creating    |
+|                               | zeros, matrix operation matmul, transforming concat,  |
+|                               | computing add, and finding argmax                     |
++-------------------------------+-------------------------------------------------------+
+| paddle.nn                     | Networking-related APIs such as Linear, Conv2d, loss  |
+|                               | function, convolution, LSTM，and activation function  |
++-------------------------------+-------------------------------------------------------+
+| paddle.static.nn              | Special APIs for networking under a static graph such |
+|                               | as input placeholder data/Input and control flow      |
+|                               | while_loop/cond                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.static                 | APIs related to the basic framework under a static    |
+|                               | graph such as Variable, Program, and Executor         |
++-------------------------------+-------------------------------------------------------+
+| paddle.framework              | Universal APIs and imprerative mode APIs such as      |
+|                               | to_variable and prepare_context                       |
++-------------------------------+-------------------------------------------------------+
+| paddld.optimizer              | APIs related to optimization algorithms such as SGD,  |
+|                               | Adagrad, and Adam                                     |
++-------------------------------+-------------------------------------------------------+
+| paddle.optimizer.lr_scheduler | APIs related to learning rate attenuation             |
+|                               |                                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.metric                 | APIs related to evaluation index computation such as  |
+|                               | accuracy and auc                                      |
++-------------------------------+-------------------------------------------------------+
+| paddle.io                     | APIs related to data input and output such as save,   |
+|                               | load, Dataset, and DataLoader                         |
++-------------------------------+-------------------------------------------------------+
+| paddle.device                 | APIs related to device management such as CPUPlace    |
+|                               | and CUDAPlace                                         |
++-------------------------------+-------------------------------------------------------+
+| paddle.distributed            | Distributed related basic APIs                        |
+|                               |                                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.distributed.fleet      | Distributed related high-level APIs                   |
+|                               |                                                       |
++-------------------------------+-------------------------------------------------------+
+| paddle.vision                 | Vision domain APIs such as datasets, data processing, |
+|                               | and commonly used basic network structures like       |
+|                               | resnet                                                |
++-------------------------------+-------------------------------------------------------+
+| paddle.text                   | NLP domain APIs such as datasets, data processing,    |
+|                               | and commonly used basic network structures like       |
+|                               | transformer                                           |
++-------------------------------+-------------------------------------------------------+

doc/paddle/api/not_display_doc_list

 paddle.utils
 paddle.incubate
+paddle.hapi

doc/paddle/faq/index_cn.rst

 ##############
-FAQ
+常见问题
 ##############
 如果您在使用Paddle框架开发过程中遇到了使用咨询类的问题，希望快速得到官方的答疑和指导，可以先来FAQ中查阅
 

doc/paddle/guides/index_cn.rst

@@ -8,7 +8,7 @@ PaddlePaddle (PArallel Distributed Deep LEarning)是一个易用、高效、灵
 
 让我们从学习PaddlePaddle基本概念这里开始：
 
-- `版本转换工具 <./migration_cn.html>`_：介绍 Paddle 1 到Paddle 2的变化与Paddle1to2转换工具的使用。
+- `版本迁移 <./migration_cn.html>`_：介绍 Paddle 1 到Paddle 2的变化与Paddle1to2转换工具的使用。
 - `动态图转静态图 <./dygraph_to_static/index_cn.html>`_：介绍 Paddle 动态图转静态图的方法 
 - `模型存储与载入 <./model_save_load_cn.html>`_：介绍 Paddle 模型与参数存储载入的方法
 

doc/paddle/guides/migration_cn.rst

-Paddle 1 to Paddle 2
+版本迁移
 ====================
 
 飞桨框架v2.0-beta，最重要的变化为API体系的全面升级以及动态图能力的全面完善。下文将简要介绍Paddle