rembert/splinter (torch) type annotations
#16059

Type annotations for Rembert & Splinter (Torch) and copies
@Rocketknight1 this passed tests - Think I was missing an Optional typing import on Splinter.
No build on PR though<|||||>The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_16207). All of your documentation changes will be reflected on that endpoint.<|||||>@Rocketknight1 Rembert and Splinter done, as well as copies from Bert.
Tests failing on flax, which wasn't modified. <|||||>Hi @jacobdineen there's a lot of changes in unrelated files here, mostly just reformatting. Did you do that manually, or did it happen when you ran something like `make style` or `make fixup`?<|||||>@Rocketknight1 The auxiliary files that were updated were results of running make fix-copies, and then make fixup. I tried several different things, but the build always failed in a single place that I wasn't able to trackdown. Something about an Optional call not defined in the model template file, which was not something that was modified.<|||||>Hi @jacobdineen, that's weird. Can you make a new PR (make sure to fork/branch from the most recent version of the library!) and just make the type hint changes to Rembert + Splinter, without any formatting changes or things like `make fixup` or `make fix-copies`? Tests will fail, but I'll review it and run the fixup myself here, and I should be able to resolve any problems at my end.

Thanks for your patience here - hopefully we can figure this one out!<|||||>@Rocketknight1 - Will do! Closing this PR now.