## Summary This PR adds special-casing for `@final` and `@override` decorator for a similar reason as https://github.com/astral-sh/ruff/pull/17591 to support the invalid overload check. Both `final` and `override` are identity functions which can be removed once `TypeVar` support is added.
Markdown files within the mdtest/ subdirectory are tests of type inference and type checking;
executed by the tests/mdtest.rs integration test.
See crates/red_knot_test/README.md for documentation of this test format.