Port the proc macro attributes to the new attribute parsing infrastructure
Ports `#[proc_macro]`, `#[proc_macro_attribute]`, `#[proc_macro_derive]` and `#[rustc_builtin_macro]` to the new attribute parsing infrastructure for https://github.com/rust-lang/rust/issues/131229#issuecomment-2971351163
I've split this PR into commits for reviewability, and left some comments to clarify things
I did 4 related attributes in one PR because they share a lot of their code and logic, and doing them separately is kind of annoying as I need to leave both the old and new parsing in place then.
r? ``@oli-obk``
cc ``@jdonszelmann``
6bd327374a