commands: use byteskwargs() in verify() Otherwise Python 3 complains about the missing key. Differential Revision: https://phab.mercurial-scm.org/D6294

match: use raw strings to avoid illegal baskslash escape Python 3.8 was complaining about the invalid escape sequences. Let's use raw strings to avoid the warning and double baskslashes. Differential Revision: https://phab.mercurial-scm.org/D6293

revbranchcache: use context manager in _writerevs() to write to file The other _writenames() is a bit complicated to use context manager. Differential Revision: https://phab.mercurial-scm.org/D6292

revbranchcache: factor logic to write names and revs in separate functions Before this patch, the write function was so populated with upto 4 level of indentation, it was hard to understand what's going on. Differential Revision: https://phab.mercurial-scm.org/D6291

tests: make log style a little easier to read in test-copytrace-heuristics.t Revision numbers are much shorter and easier to read (especially compared to the full nodeids that were used here), so I switched to that. That's also what almost all the commands used (e.g. `hg rebase -s . -d 1`). I updated the two instances that used nodeids. I also made some other little cleanups to the log templates. Differential Revision: https://phab.mercurial-scm.org/D6279

tests: avoid cryptic nodeids in tests/test-rename-merge1.t These two nodeids had not been part of any output before, so one can't know which revision they refer to without adding something like `hg log` before them. It turned out that '.^' was equivalent for both of them, so that's what I replaced them with. Differential Revision: https://phab.mercurial-scm.org/D6280

tests: defines aliases for `hg log` calls in test-copytrace-heuristics.t This also makes the test cases more consistent since a few had missed the ":" in "changeset:" that the others used. Differential Revision: https://phab.mercurial-scm.org/D6278