Simplify `typing.evaluate_forward_ref`

[JelleZijlstra]

Bug report

In PEP-749 I added typing.evaluate_forward_ref to replace the private typing.ForwardRef._evaluate, which is being used by some external users.

The current documentation claims these differences from annotationlib.ForwardRef.evaluate:

1. Recursively evaluates forward references nested within the type hint.
2. Raises TypeError when it encounters certain objects that are not valid type hints.
3. Replaces type hints that evaluate to None with types.NoneType.
4. Supports the FORWARDREF and STRING formats.

(1) is useful and fits well with the typing module; annotationlib can't do this because it requires introspecting into typing-specific objects. (2) I feel is not useful (compare #133959): the type check is not particularly thorough, and it's generally better for callers to allow more objects through that callers can handle on their own terms. (3) is sort of harmless but not particularly useful. (4) is not true any more since I also added support for these formats to ForwardRef.evaluate.

So I'd like to drop differences 2 through 4, leaving the function focused on recursively evaluating nested ForwardRefs.

Linked PRs

• gh-133960: Improve typing.evaluate_forward_ref #133961
• [3.14] gh-133960: Improve typing.evaluate_forward_ref (GH-133961) #134663