Add type hints

[ClementPinard]

Add type hints to the library. It makes it much easier to work with VSCode since you get the autocompletion.

Notes :

• type hints are 3.8 style (aka very verbose) and might be much prettier if converted to 3.10 style
• Some automatic formatting have been added, I will remove it
• This is not typechecked by pyright or mypy. the type hints are only for information purpose. Maybe this could be put in a stub file instead ?

[ClementPinard]

Hi, is this PR considered ?
Helped me a lot for auto completion, and would be nice to have it included in the pip package (which could use an update on HF's acclerate version dependency btw)

Cheers,
Clément

[Chris-hughes10]

Hi @ClementPinard, I believe that @bepuca was looking at this

[ClementPinard]

Hi thanks @Chris-hughes10 don't hesistate to ping me if some changes are needed