branching: merge stable into default

Added signature for changeset c083d9776cb2

Added tag 6.5.3 for changeset c083d9776cb2

relnotes: add 6.5.3

revlog: avoid opening and closing the file for each cloned revision The previous code was flushing files after each new revision, slowing things down. For exemple, with this change, the evolve repository can run `hg debugupgraderepo --run --optimize re-delta-parent` in about 3.4s instead of 4.5 seconds.

censor: accept censored revision during upgrade They can simply be passed by as censored.

censor: show that censored revision prevent repository upgrade This is not great.

smartset: don't ignore hidden revs when intersecting This fixes the bug I demonstrated in the previous commit, but I'm not sure at all if it's the right way of doing it.

tests: demonstrate crash in `unstable()` with internal-phase orphans

rust-matchers: fix quadratic complexity in `FileMatcher` Concretely, this command: ``` $ echo hg up -r <nodeid>; time hg revert dir1 dir2 -r <othernode> --debug hg up -r <nodeid> real 0m14.690s user 0m14.766s sys 0m5.430s ``` was much slower despite using 16 cores before this change. The approach taken here is the same one used in match.py, in exactmatcher. This changeset was originally written by Valentin Gatien-Baron in a private repository. I have redacted the commit message and did a minor clean up of the code.