Auto merge of #53459 - petrochenkov:stabmore, r=nrc
Stabilize a few secondary macro features
- `tool_attributes` - closes https://github.com/rust-lang/rust/issues/44690
- `proc_macro_path_invoc` - this feature was created due to issues with tool attributes (https://github.com/rust-lang/rust/issues/51277), those issues are now fixed (https://github.com/rust-lang/rust/pull/52841)
- partially `proc_macro_gen` - this feature was created due to issue https://github.com/rust-lang/rust/issues/50504, the issue is now fixed (https://github.com/rust-lang/rust/pull/51952), so proc macros can generate modules. They still can't generate `macro_rules` items though due to unclear hygiene interactions.