Docs: add `kwargs` type to fix formatting
# What does this PR do?

As the title indicates: in several places our docs `kwargs` did not include its type, which made our doc builder treat it like a continuation of the previous parameter 💔 

Example of currently broken docs ([this function](https://huggingface.co/docs/transformers/v4.30.0/en/main_classes/processors#transformers.ProcessorMixin.save_pretrained)):
<img width="915" alt="Screenshot 2023-07-10 at 18 20 47" src="https://github.com/huggingface/transformers/assets/12240844/d027950f-7082-416a-b2da-e4f3712bd27c">

This PR is a result of CMD+F on the broken pattern, and applying the fix :)
_The documentation is not available anymore as the PR was closed or merged._<|||||>After the PR (as seen in the doc preview):
<img width="926" alt="Screenshot 2023-07-10 at 18 55 21" src="https://github.com/huggingface/transformers/assets/12240844/9329186d-86ee-4091-a5c5-bbee77ab83f7">
<|||||>Happy to push a `doc-builder` side change if needed  -- and to do the opposite of this PR: remove `Dict[str, Any]` from `kwargs` whenever it is present.

Just let me know your preference :) If it's neutral for you, I think having the explicit type is friendly for Python newbies.<|||||>@amyeroberts if you don't oppose, I'll merge this PR 🤗 <|||||>@gante Go for it! 