Auto merge of #74019 - Manishearth:rollup-2st3jsk, r=Manishearth
Rollup of 12 pull requests
Successful merges:
- #73140 (Fallback to xml.etree.ElementTree)
- #73670 (Add `format_args_capture` feature)
- #73693 (Use exhaustive match in const_prop.rs)
- #73845 (Use &raw in A|Rc::as_ptr)
- #73861 (Create E0768)
- #73881 (Standardize bibliographic citations in rustc API docs)
- #73925 (Improve comments from #72617, as suggested by RalfJung)
- #73949 ([mir-opt] Fix mis-optimization and other issues with the SimplifyArmIdentity pass)
- #73984 (Edit docs for rustc_data_structures::graph::scc)
- #73985 (Fix "getting started" link)
- #73997 (fix typo)
- #73999 (Bump mingw-check CI image from Ubuntu 16.04 to 18.04.)