docs: Resolve many typos in the English docs
# What does this PR do?

* Fixes typo in `python -m transformers.onnx --help`.
* Fixes many typos in the English documentation via `codespell`.

- [x] This PR fixes a typo or improves the docs

## Who can review?

Documentation: @sgugger

- Tom Aarsen
_The documentation is not available anymore as the PR was closed or merged._