fix sign op input error check
test=develop

* 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

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

* refine 13 en doc

* fix the precise roi poop op test=develop
add roi backward implementation, fix the output-channel

* Add fp16 in input.dtype check test=develop

* Add warning of fp16 in CPU test=develop

* add unittest code for fp16 test=develop

* fix float16 list error test=develop

* Polish En doc for some APIs
* Update some comments and API.spec

* modify english api test=develop test=document_fix

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

* fix English Doc of API:layers.py_func/sum

fix APIs, to_variable、NCE、PRelu、softmax、rankloss for dygraph, test=document_fix, test=develop (#20142)

* 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

Fix english doc api: sequence_slice, sigmoid_cross_entropy_with_logits, ssd_loss, DetectionMAP, detection_map (#20405)

* Fix english doc api: sequence_slice, sigmoid_cross_entropy_with_logits, ssd_loss, DetectionMAP, detection_map

* Fix several api docs

test=develop, test=document_fix

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

* 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 English document, test=document_fix

* update api.spec, test=document_fix

* update api.spec, test=document_fix

* update, test=document_fix

* update the api en_doc of has_inf, has_nan, cumsum, double_buffer and mul, test=document_fix

* update the API.spec for apis, test=document_fix

* fix expand bug test=develop

* fix style test=develop

* fix style test=develop

* fix style test=develop

* fix style test=develop

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

* update sample code, test=document_fix, test=develop

* fix sample typo, test=document_fix, test=develop

* modify document of 11 APIs
test=develop
test=document_fix

* fix dtype to data type and description of name parameter

* update norm op, test=develop, test=document_fix

* fix norm api, test=develop, test=document_fix

* refine en doc. test=develop. test=document_fix

* test=document_fix
Fix english doc api, invloves the op of greater_equal,greater_than,less_equal,not_equal,
rank,rsqrt,diag,linspace,reduce_all,reduce_any,sign,where,zeros_like,unique_with_counts.

* Fix some format problem in the op of sign and greather_than.
test=develop
test=document_fix

* Fix the example of zeros_like, and update api.spec
test=develop
test=document_fix

* 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

* refine Normal Uniform documnet

* fix fluid.data code example, test=develop, test=document_preview, test=document_fix

enhance shape error messages for reshape op.
test=develop

* 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

* Add detailed error messages for nce layer

test=develop

* Fix some problems

test=develop

* Fix unit test coverage

test=develop

test=develop

* fix en_doc of one-hot and embedding test=develop, test=document_fix

* modify into fluid.data test=develop, test=document_fix

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

* fix api.spec conflict, test=develop, test=document_fix