[`Umt5`] Add google's umt5 to `transformers` (#24477)

* add tokenization template

* update conversion script

* update modeling code

* update

* update convert checkpoint

* update modeling

* revert changes on convert script

* new conversion script for new format

* correct position bias

* cleaning a bit

* Credit co authors

Co-authored-by: agemagician
<[email protected]>

Co-authored-by: stefan-it
<>

* styling

* Add docq

* fix copies

* add co author

* Other Author

* Merge branch 'main' of https://github.com/huggingface/transformers into add-umt5

* add testing

* nit

* Update docs/source/en/model_doc/umt5.mdx

Co-authored-by: Stefan Schweter <[email protected]>

* fix t5

* actual fix?

* revert wrong changes

* remove

* update test

* more fixes

* revert some changes

* add SPIECE_UNDERLINE

* add a commone xample

* upfate

* fix copies

* revert changes on t5 conversion script

* revert bytefallback changes since there was no addition yet

* fixup

* fixup

* ingore umt5 cutom testing folder

* fix readmes

* revertT5 changes

* same outputs

* fixup

* update example

* Apply suggestions from code review

* style

* draft addition of all new files

* current update

* fix attention and stuff

* finish refactoring

* auto config

* fixup

* more nits

* add umt5 to init

* use md format

* Update README.md

Co-authored-by: Sylvain Gugger <[email protected]>

* revert changes on mt5

* revert mt4 changes

* update test

* more fixes

* add to mapping

* fix-copies

* fix copies

* foix retain grad

* fix some tests

* nits

* done

* Update src/transformers/models/umt5/modeling_umt5.py

Co-authored-by: Sylvain Gugger <[email protected]>

* Update docs/source/en/model_doc/umt5.md

* Update src/transformers/models/umt5/__init__.py

* Update docs/source/en/model_doc/umt5.md

Co-authored-by: Stefan Schweter <[email protected]>

* Update src/transformers/models/umt5/modeling_umt5.py

* update conversion script + use google checkpoints

* nits

* update test and modelling

* stash slow convert

* update fixupd

* don't change slow

---------

Co-authored-by: stefan-it <>
Co-authored-by: Stefan Schweter <[email protected]>
Co-authored-by: Sylvain Gugger <[email protected]>