* add cn doc of trace API

* modified sample code of add_position_encoding to 2.0

* add cn doc of trace API

* modified doc of warpctc  ctc_loss and CTCLoss, add support float64 of log_probs

* add Tensor concept introduction

* add Tensor concept introduction

* add Tensor concept introduction

* add Tensor concept introduction

* add Tensor concept introduction

* fix example code

* refine doc of stack

* update paddle api

* fix typo

* fix doc

* fix sample code

* fix code-block

* update doc fix for some ops, test=develop

* udpate the doc for asin, cos, atan, test=develop

add the doc for the logic ops, add the broadcasting ops

* add float16 dtype, test=develop

* add type for unique

* add unique doc

* add unique doc

* Add chinese and english documents of paddle.prod

test=develop

* refine sign tanh api, test=develop

* Add Tanh, test=develop

* fix en, test=develop

* Add DecodeHelper cn docs.

* Update Seq2Seq API cn doc.

* Fix BasicDecoder sample code.

* Fix TrainingHelper, GreedyEmbeddingHelper, SampleEmbeddingHelper and BasicDecoder sample code in cn docs.

* Add cholesky api cn docs.
Co-authored-by: NFrostML <380185688@qq.com>

* Update docs for `abs` `acos` `asin` `atan` `ceil` `cos`

update code samples
`Variable` -> `Tensor`
remove activation wording
explain cos input/output range
misc fixes

* Apply input template

* Update `enable_imperative` -> `disable_static`

fix unstack cn doc

 Fix the compare ops doc for the api2.0

fix nce docstring for python 3

fix reorder_lod_tensor_by_rank example

Fix the doc examples for those apis

* modify the doc, test=develop