rust-pathauditor: use interior mutability for use in multi-threaded contexts The usual recommendation for using `RwLock` or `Mutex` is that if there are about as many write as there are reads, use `Mutex`, and if there are more reads than writes, use `RwLock`. If after the main bottleneck (i.e. parallel traversal) is removed this shows up on profiles, we should investigate using the `parking_lot` since we don't need a poisoning API, or maybe move to different types of caches entirely. Differential Revision: https://phab.mercurial-scm.org/D8213

rust-pathauditor: actually populate the `audited_dirs` cache I forgot this when rewriting this logic during the review process. Differential Revision: https://phab.mercurial-scm.org/D8212

rust-pathauditor: actually split Windows shortname aliases at `~` Right now, splitting with a max of 1 parts is useless. Differential Revision: https://phab.mercurial-scm.org/D8211

debuginstall: add entry about re2 Rust bindings when applicable Differential Revision: https://phab.mercurial-scm.org/D8226

rust-cpython: add `debug` module to expose debug information to Python This will be mostly used in `debuginstall`. Differential Revision: https://phab.mercurial-scm.org/D8225

rust-status: use bare hg status fastpath from Python This change also adds a test case for subrepos. Repeating the benchmark information from the `hg-core` commit: On the Netbeans repository: C: 840ms Rust+C: 556ms Mozilla Central with the one pattern that causes a fallback removed: C: 2.315s Rust+C: 1.700s Differential Revision: https://phab.mercurial-scm.org/D7931

rust-status: update rust-cpython bridge to account for the changes in core Differential Revision: https://phab.mercurial-scm.org/D7930

rust-status: add bare `hg status` support in hg-core A lot of performance remains to be gained, most notably by doing more things in parallel, but also by caching, not falling back to Python but switching to another regex engine, etc.. I have measured on multiple repositories that this change, when in combination with the next two patches, improve bare `hg status` performance, and has no observable impact when falling back (because it does so early). On the Netbeans repository: C: 840ms Rust+C: 556ms Mozilla Central with the one pattern that causes a fallback removed: C: 2.315s Rust+C: 1.700 s Differential Revision: https://phab.mercurial-scm.org/D7929