0360c6b219
## Summary Part of #15382, this PR adds support for calling a variable that's annotated with `typing.Callable`. ## Test Plan Add test cases in a new `call/annotation.md` file.
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.