Add forward reference annotation detection

[Joko013]

Adding support for parsing forward references in type annotations and using them for the detection algorithm.

Description

Hi, I'd like to add the support for forward references so I would appreciate it if you could take a look at this draft.

I understand that it has been discussed but I think it's worth reconsidering, given the timeframe (the original discussion is from 2020) and further adoption of new Python versions.

Personally, this blocks the usage of Vulture as it either forces you to adopt a new standard (from __future__ import annotations instead of if TYPE_CHECKING:...) or deal with a lot of false positives if you don't (or can't).

I know that in the original discussion, there's been concerns about the issues that this could open up so I've tried to cover some basic cases but I'm all for for covering more.

Let me know if this approach makes sense to you.

Related Issue

• Support Forward References for Annotations #216

Checklist:

• I have updated the documentation in the README.md file or my changes don't require an update.
• I have added an entry in CHANGELOG.md.
• I have added or adapted tests to cover my changes.
• I have run pre-commit run --all-files to format and lint my code.

[jendrikseipp]

Thanks for the PR! I'll take a look when I find the time.