histedit: cache description line
Navigating the curses-based histedit interface can be pretty slow
because it redraws everything whenever you make a change.
This patch simply replaces `@property` by `@util.propertycache` on the
`histeditrule.desc()` function so it's not re-calculated every time
the screen needs to be re-rendered. I timed it on an example of 30
simple commits, where I moved the top commit down 25 steps and then up
25 steps after. Before this patch, that (the whole `hg histedit`
invocation) took 11.6 s of CPU and after this patch it took 0.8 s).
Differential Revision: https://phab.mercurial-scm.org/D9016
syntax: glob
*.elc
*.tmp
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.dll
*.exe
*.pyd
*.pyc
*.pyo
*$py.class
*.swp
*.prof
*.zip
\#*\#
.\#*
tests/artifacts/cache/big-file-churn.hg
tests/.coverage*
tests/.testtimes*
tests/.hypothesis
tests/hypothesis-generated
tests/annotated
tests/exceptions
tests/*.err
tests/htmlcov
build
contrib/chg/chg
contrib/hgsh/hgsh
contrib/vagrant/.vagrant
dist
packages
doc/common.txt
doc/*.[0-9]
doc/*.[0-9].txt
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
MANIFEST.in
patches
mercurial/__modulepolicy__.py
mercurial/__version__.py
mercurial/hgpythonlib.h
mercurial.egg-info
.DS_Store
tags
cscope.*
.idea/*
.asv/*
.pytype/*
.mypy_cache
i18n/hg.pot
locale/*/LC_MESSAGES/hg.mo
hgext/__index__.py
rust/target/
rust/*/target/
# Generated wheels
wheelhouse/
syntax: regexp
^\.pc/
^\.(pydev)?project
# hackable windows distribution additions
^hg-python
^hg.py$