11b5cbcd2f
## Summary This is a pure restructuring of the `attributes.md` and `descriptor_protocol.md` test suites. They have grown organically and I didn't want to make major structural changes in my recent PR to keep the diff clean.
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.