setuptools ANN201 autofixes for fully untyped functions

[Avasam]

Summary of changes

I commented [lint.per-file-ignores] "setuptools/**" = ["ANN2"] and [lint.flake8-annotations] ignore-fully-untyped = true in ruff.toml then ran ruff check setuptools --select=ANN201 --fix --unsafe-fixes.
I removed the added return types that were revealing hidden mypy issues (often initialize_options) to keep the changes here completely automated.

This has some overlap with #4709, but they can be merged in either order.

Pull Request Checklist

• Changes have tests (this increased the amount of type-checked code)
• News fragment added in newsfragments/. (no public facing changes)
  (See documentation for details)

[abravalheri]

Ok, isn't this going to make more complicated inheritance and require some form of overload annotation later?

It is kind of an abstract method that needs to be implemented.
The expected signature is something like () -> dict[str, Callable[[str], Any]] or more specific¹.
I suppose that for the sake of documentation/understanding that return value as a dict is better than NoReturn.

Footnotes

1. The return values for the callable are probably something like all the types that can be produced by ast.parse_literal (or subtypes) + packaging.specifiers.SpecifierSet ↩

[Avasam]

NoReturn is a bottom type, so as far as subclassing it shouldn't be an issue.

For consumers it means that if something returns a ConfigHandler, they'd see accessing the property parsers as never returning (unless they use isinstance to ensure a subtype or something).

So you are correct that

I suppose that for the sake of documentation/understanding that return value as a dict is better than NoReturn.

Even better, this property should be marked abstract, so type-checkers tells the dev to never instanciate ConfigHandler directly, which implies that any ConfigHandler the dev gets should be a concrete subclass, so returning NoReturn for a NotImplementedError is no longer relevant.

But that's for a separate PR ! (I'll just revert this line here)

[abravalheri]

Thank you very much.