relnotes: add API change note per request in D8502 Differential Revision: https://phab.mercurial-scm.org/D8549

merge with stable

grep: grep the working copy faster `hg grep qqqq` in the mercurial repo: before: 0,859s after: 0,233s `hg grep somethingwithnomatch` in mozilla-central: before: 51s after: 19s This is probably also a tiny bug fix, because the code was looking up a node for filename `pfn` on a filelog for filename `fn`, which are most of the time the same filename, but don't have to be. Ignoring performance and the bug fix, the code should have the same behavior. Differential Revision: https://phab.mercurial-scm.org/D8545

grep: stop computing information for --diff when unnecessary This is one reason why `hg grep pattern` essentially does `hg cat -r . 'set:**'` inside. There is no speed improvement in this commit, because the rest of the code still greps data from filelog instead of working copy when possible. Differential Revision: https://phab.mercurial-scm.org/D8544

grep: don't go in an infinite loop when given empty regex Differential Revision: https://phab.mercurial-scm.org/D8543

grep: improve test coverage Differential Revision: https://phab.mercurial-scm.org/D8542

phabricator: avoid passing None to pycompat.fsdecode Differential Revision: https://phab.mercurial-scm.org/D8525

setup: stop asking cargo to spam It prints this kind of stuff by default: Compiling regex v1.3.6 Compiling rand v0.7.3 Compiling crossbeam-deque v0.7.3 which is way better than we ask for before this change, which is screen after screen of compilation commands and irrelevant warnings in crates we use. Differential Revision: https://phab.mercurial-scm.org/D8537

git: implement some changelog methods Differential Revision: https://phab.mercurial-scm.org/D8540

git: avoid looking-up parents for the null commit Differential Revision: https://phab.mercurial-scm.org/D8541