* improve MSRAInitializer

* improve the doc

* calculate_gain; test=document_fix

* Constant; test=document_fix

* KaimingNormal; test=document_fix

* KaimingUniform; test=document_fix

* randint; test=document_fix

* squeeze;test=document_fix

* argmin; test=document_fix

* argmin; test=document_fix

* triu; test=document_fix

* add_n;test=document_fix

* unique; test=document_fix

* topk; test=document_fix

* squeeze;test=document_fix

* randint;test=document_fix

* argmin; test=document_fix

* constant; test=document_fix

* constant; test=document_fix

* KaimingNormal; test=document_fix

* kaiming; test=document_fix

* unique; test=document_fix

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* fix paddle.optimizer test=document_fix

* fix paddle.optimizer test=document_fix

* fix bugs in paddle.nn.functional document test=document_fix

* fix bugs in paddle.nn.functional document test=document_fix

* fix bugs in paddle.nn.functional document test=document_fix

* fix bugs in paddle.nn.functional document test=document_fix

* fix nn formula bugs test=document_fix

* fix nn formula bugs test=document_fix

* fix nn formula bugs test=document_fix

add __all__=[] to python files not in API public list; import * only support in API public list files (#32643)

* update 2.0 public api in nn

* replace Chinese character cause error in ci;synchronization with pr:#32588 to avoid 'ascii' codec in python2

* numbers used in paddle.nn.functional.norm but not imported

* upgrade comment string to raw string

* fix string in

* fix string with ' '

* revert update on comments

* upgrade only necessary

* fix sample code checker

* fix comments with '''

Add api of KaimingUniform & KaimingNormal in paddle.nn.initializer