* fix Varaible doc

* fix LOD to LoD

* fix LOD to LoD

* test=develop, refine doc

* test=develop, refine doc

* test=develop, refine doc and example code of Variable_cn.rst

* fix Print, is_empty, read_file op' cn doc test=develop

fix the doc of API:fluid.layers.py_func

According to the latest documentation standards：

* fix the document of API:fluid.Layers.sum

* fix the document of API:fluid.Layers.sum

* fix the document of API:fluid.Layers.sum

* fix the chinese doc for paddle test=develop
paddle.fluid.layers.create_global_var
paddle.fluid.layers.create_parameter
paddle.fluid.optimizer.FtrlOptimizer
paddle.fluid.optimizer.LarsMomentumOptimizer
paddle.fluid.optimizer.MomentumOptimizer
paddle.fluid.optimizer.RMSPropOptimizer
paddle.fluid.optimizer.SGDOptimizer

* Refine StaticRNN api doc

test=develop
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* Refine StaticRNN api doc
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* fix 5 api_cn documents
test=document_preview

* modify io_map_readers

* Refine topk op api doc.

test=develop
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* refine top k api doc
Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* polish decayed adagrad opt zh api doc

* change the note position

* delete return and return type

* polish details

* use whole optimizer name

* polish adamax optimizer zh doc

* polish details

* use whole optimizer name

* polish adam optimizer zh api doc

* polish details

* polish adagrad optimizer api zh doc

* polish details

* refine fluid.layers.one_hot

* update one_hot doc

* fix code error

* refine docs of CUDA and CPU places, test=develop

* refine docs of CUDA and CPU places, test=develop

* refine cuda_pinned_places, test=develop

* refine, test=develop

* refine, test=develop

* polish seven minimize api zh doc

* polish details

* enrich grad_clip param comment

* (4) modify reorder_lod_tensor_by_rank doc

* refine scope_guard_cn, test=develop

* refine scope_guard_cn, test=develop

* refine, test=develop

* refine, test=develop

update uniform_random_batch_size_like_cn.rst

* refine api docs name param

* add name param refine for ifelse,round,sqrt,sin,scatter,test=develop

* refine name according the new standard test=develop

* refine name according the new standard test=develop

* test=document_preview

* refine cn doc

* refine cn doc

* refine cn doc

* refine cn doc

* Fix elu op doc
test=document_preview

* fix elu
test=document_preview

test=develop

* update uniform_random_cn.rst,test=develop

* modify WeightNormParamAttr doc

* modify

* modify WeightNormParamAttr

* modify

* modify

* modify

* test

* test

* test=develop

* add params declearation

* add declearation

* test

* fix Varaible doc

* fix LOD to LoD

* fix LOD to LoD

* test=develop, refine doc

* test=develop, refine doc

test=develop

test=develop

* add RecomputeOptimizer_cn.rst

* modify RecomputeOptimizer_cn.rst
test=develop

* modify RecomputeOptimizer_cn.rst
test=document_preview

* modify RecomputeOptimizer_cn.rst, test=document_fix

* modify optimizer_cn.rst. test=document_fix

* modify optimizer_cn.rst. test=document_fix

* modify RecomputeOptimizer_cn.rst, test=document_fix

* add LookaheadOptimizer_cn.rst (#1360)

* add LookaheadOptimizer_cn.rst
test=document_preview

* modify LookaheadOptimizer_cn.rst, test=document_fix

* modify LookaheadOptimizer_cn.rst, test=document_fix

* modify LookaheadOptimizer_cn.rst, test=document_fix

* modify RecomputeOptimizer_cn.rst, test=document_fix

* delete unused files

update cn doc for im2sequence , mean_iou, pad2d, range

* modify io.compose inference doc