Summary

This is similar to #8876, but more limited in scope:

1. It only applies to # fmt: skip (like Black). Like # isort: on, # fmt: on needs to be on its own line (still).
2. It only delimits on #, so you can do # fmt: skip # noqa, but not # fmt: skip - some other content or # fmt: skip; noqa.

If we want to support the ;-delimited version, we should revisit later, since we don't support that in the linter (so # fmt: skip; noqa wouldn't register a noqa).

Closes #8892.