Add documentation for BertJapanese (#11219)
* Start writing BERT-Japanese doc
* Fix typo, Update toctree
* Modify model file to use comment for document, Add examples
* Clean bert_japanese by make style
* Apply suggestions from code review
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
* Split a big code block into two
* Apply suggestions from code review
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
* Add prefix >>> to all lines in code blocks
* Clean bert_japanese by make fixup
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
