[flake8-pyi] Fix more complex cases (PYI019)

[InSyncWithFoo]

Summary

Resolves #15798.

PYI019 is now a binding-based rule. All references to the type variable will now be replaced correctly. As a result, the fix is now safe in most cases; when that is not possible, its applicability remains display-only. Additionally, for a safe fix, comments within the fix ranges will cause it to be marked as unsafe.

Previously, there was also a small bug that would cause a PEP 695 type variable not to be removed correctly were it to be placed at the very end of the type parameter list. This has been fixed as well.

# Original
def f[T, S](self: S) -> S: ...

# Before
def f[TS](self) -> Self: ...

# After
def f[T](self) -> Self: ...

Test Plan

cargo nextest run and cargo insta test.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.