* fix API:cos, exp, ceil, elu, brelu English doc
test=develop
test=document_fix

* Fix api docs. test=document-fix

* Fix en docs. test=develop

* Fix the doc of dynamic_gru. test=document_fix

* Update API.spec. test=document_fix

* Fix codestyle test=develop, test=document_fix

test=document_fix

* fix Print, is_empty, read_file test=document_fix

* cherry-pick fix prroi op test=develop test=release/1.6

* cherry pick , 1.6 fix bug node fc sort

* cherry pick , 1.6 fix bug node fc sort

* cherry pick , 1.6 fix bug node fc sort, test=release/1.6

* cherry pick , 1.6 fix bug node fc sort& datanorm double, test=release/1.6

test=develop
test=release/1.6
test=document_fix

* Fix transpiler en doc (#20149)

* test=develop,test=document_fix,fix transpiler doc,add API.spec

* test=develop,test=document_fix,fix transpiler doc,add API.spec

cherry pick 91693b9c and resolve conflict in API.spec, test=document_fix (#20477)

modify en api doc

- leaky_relu
- less_than 
- log
- logical_and
- logical_or
- logical_xor
- logical_not

test=release/1.6

[cherry-pick] Polish en doc of LoDTensorArray, test=document_fix, test=release/1.6 (#19972) (#20426)

* fix some en doc test=develop test=document_fix

* fix new fluid.data API.spec test=develop test=document_fix

* fix typo test=develop, test=document_fix

* fix typo test=develop test=document_fix

* fix typo test=develop test=document_fix

* fix test=develop test=document_fix

* fix according review test=develop test=document_fix

* fix review test=develop test=document_fix

* fix according review advice test=develop test=document_fix

* fix the doc  test=develop test=document_fix

* fix API.spec test=develop test=document_fix

Modify doc for shuffle, firstn, save_vars, load_vars, L1DecayRegularizer, L2DecayRegularizer (#20287) (#20470)

* modify shuffle, firstn, regularizer, load_vars, save_vars, test=develop, test=document_fix

* test=document_fix, test=release/1.6, refine en doc (#20317)

* 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, Refine en doc (#20409)

* 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=document_fix, fix BackwardStrategy English Doc

* test=document_fix, fix syntax

* test=document_fix, refresh API.spec

* test=document_fix, refine api spec

* test=document_fix, refine api spec

* test=release/1.6, test=document_fix, remove useless files

Cherrypick  en doc: reorder_lod_tensor_by_rank , map_reader, WeightNormParamAttr, io.compose  (#20463)

* modify map_reader en doc (#20229)

* modify WeightNormParamAttr en doc (#20218)

* modify reorder_lod_tensor_by_rank en doc

* modify compose en doc (#20217)

update the api doc of BuildStrategy and its settings

refine en api doc of [shape, scale, split, selu, soft_relu, scatter], test=develop, test=document_fix (#20264) (#20458)

* add new save load interface; test=develop

* add new save interface; test=develop

* add save load interface ;

* fix save load error;

* fix dygraph set dict bug;

* add save load unit test; test=develop

* fix test_imperative_optimizer bug; test=develop

* fix unitest optimizer bug; test=develop

* fix code coverage; test=develop

* fix converage; test=develop

* add document for apis; test=develop

* fix unitest error; test=develop

* fix save load unit test error; test=develop

* fix error message; test=develop

* change set_parameter set_optimizer to save_dygraph; test=develop

* add load_graph check; test=develop

* fix api spec; test=develop

Fix the api input type and data dtype check in the op of sign
test=release/1.6

* fix the reduce api en doc test=document_fix test=develop

* fix the fluid.data test=develop test=document_fix

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

* fix according the review test=develop test=document_fix

* fix the confilict test=develop test=document_fix

update the api en_doc of has_inf, has_nan, cumsum, double_buffer and mul

* rm unused ckpt and sort ckpt

* cherry pick test=develop

* cleanup test=develop test=release/1.6

* cleanup test=develop test=release/1.6

* add api check in fc test=develop

* enforce shape error info of sum op test=develop

* fix spelling test=develop

* print x_dims info test=develop

* enhance shape error info test=develop

test=release/1.6, test=document_fix