test=release/1.6

* cherry-pick fix en doc test=develop test=document_fix

* roll back fsp_matrix hash test=develop test=document_fix

Fix english doc api, invloves the op of retinanet_target_assign, sigmoid_focal_loss and retinanet_detection_output, cherry-pick, (#20419)

test=release/1.6
test=document_fix

* polish executor doc
test=develop

* polish compiler and executor

* polish doc
test=document_fix test=develop

* Update doc
test=document_fix

* fix fluid.data
test=document_fix

* fix doc batch dim
test=document_fix

fix fleet_desc delete_after_unseen_day bug in node.py 

improve the docs of load_inference_model&load_params&load_persistables&chain. test=document_fix (#20408)

* test=develop, fix docker with paddle nccl problem

* test=develop, refine en_doc for Variable and Program

* test=document_fix, fix English doc for Variable and Program

* test=document_fix, refine astype code block style

* test=document_fix, add example code for Variable properties

test=release/1.6, test=document_fix

test=release/1.6, test=document_fix

* Fix some english doc api, shenze tools group, cherry-pick(#20300)
test=release/1.6
test=document_fix

* remote the unless change from cherry-pick
test=release/1.6
test=document_fix

* Merge branch 'develop' of https://github.com/PaddlePaddle/Paddle into api_fix

* test=release/1.6, test=document_fix

* fix en api doc test=develop test=document_fix test=document_preview

* update api.spec  test=develop test=document_fix test=document_preview

* fix some details  test=develop test=document_fix test=document_preview

* update API.spec test=document_fix test=document_preview  test=develop

* Add support for None for fluid.data (#20228)

* Refine Error Message for New Data API (#20204)

* Modify English doc of fluid.data (#20248)

* cherry pick for 131b1dc3, test=develop, test=document_fix

* cherry pick for fb21a743, test=develop, test=document_fix

[cherry-pick]fix English document of expand/pow/reshape/slice. test=release/1.6, test=document_fix (#20280) (#20356)

* Delete PadFuntion, include padding.h instead.

* move function(IsSymmetricPadding) from conv_cudnn_op.cu/conv_transpose_cudnn_op.cu to padding.h.

* fix api 1.6 doc bpr, data_norm teacher_student

* Polish english apis' doc (#20198)

* refine Normal Uniform documnet

* refine eng doc, test=release/1.6, test=document_fix

* polish en api,test=develop,test=document_fix

* modified api.spec, test=develop,test=document_fix

* modified ops for arc,test=develop,test=document_fix

* update for 1.6, test=develop,test=document_fix

* update API.spec

* Update API.spec

test=develop,test=document_fix

* Update API.spec

test=develop,test=document_fix

* refine fc/seq_conv/seq_concat en doc test=develop, test=document_fix

* refine seq_pool/reshape/reverse test=develop, test=document_fix (#20233)

* fix en_doc api of one-hot and embedding (#20187)

* Add detailed error messages for nce layer

* Fix some problems

* Fix unit test coverage

test=release/1.6

* [cherry-pick] modified doc of group_norm, test=release/1.6, test=document_fix (#20234)

* [cherry-pick] modified doc of crop_tensor, test=release/1.6, test=document_fix (#20203)

* Add capi for fluid inference api (#20092)

* add capi for fluid inference api, including AnalysisConfig, AnalysisPredictor, PaddleBuf, PaddleTensor, ZeroCopyTensor

* add dll to inference capi (#20180)

* add dll to inference capi, test=develop

* add if win32 in cmakelists, test=develop

* Update apiexample (#20247), test=develop, test=document_fix

* update api example, test=develop, test=document_fix

* update api.spec, test=release/1.6, test=document_fix

test=release/1.6 test=document_fix

test=release/1.6

* fix APIs,test=develop,test=document_fix

* fix conflict, test=develop, test=document_fix

* fix confict, test=develop, test=document_fix

* fix confict, test=develop, test=document_fix

* fix API.spec, test=develop, test=document_fix

* change fluid.layers.data to fluid.data,test=develop, test=document_fix

* fix bug on example code, test=develop, test=document_fix

* fix API.spec,  test=develop, test=document_fix

* fix the error message for reduce_mean and reduce_sum op (#20063)

* fix the error message for reduce_mean and reduce_sum op test=develop

* fix typo test=develop

* fix according review advice test=develop

* fix the test test=develop

* fix test=develop

* Fill constant error message fix (#20075)

* fix the constant error message test=develop

* fix typo test=develop

* fix typo test=develop

* fix code style test=develop

* fix comment and bugs test=develop

* fix the bug test=develop

* fix and add unittest test=develop

* fix the typo test=develop

* add support for the fill_constant op test=develop

* add test for ci coverage test=develop

test=release/1.6, test=document_fix

* update en doc