ruff

29bf2cd2 - [ty] Support implicit type of `cls` in signatures (#21771)

[ty] Support implicit type of `cls` in signatures (#21771) ## Summary Extends https://github.com/astral-sh/ruff/pull/20517 to support the implicit type of `cls` in `@classmethod` signatures. Part of https://github.com/astral-sh/ty/issues/159.