[DOCS] Example for `LogitsProcessor` class
# What does this PR do?
Added some doc string to `RepetitionPenaltyLogitsProcessor` with some examples as well.
@gante let me know if there's anything else I should add or remove from the docs.

Fixes # (issue)
#24783

## Before submitting
- [X] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
You'll probably need to run `make fixup` before you next commit :)<|||||>Previously I was having some problems with `make fixup` but now it's done and reformatted, I really like how the Makefile is structured. <|||||>@sgugger note: the weird part of the diff seems innocuous 🤔 <|||||>_The documentation is not available anymore as the PR was closed or merged._<|||||>@sgugger I have addressed all the suggested changes. <|||||>Thanks!<|||||>The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_24848). All of your documentation changes will be reflected on that endpoint.