Mention the all selector in the ty.json's schema (so that users get auto completion for all)

This should be here https://github.com/astral-sh/ruff/blob/bc3b60bf17e89beb43ea44e1a4117923103525a8/crates/ty_project/src/metadata/options.rs#L1825-L1869