discovery: use stable sort order in --new-branch warning
A Python set seems to do this already when you iterate over it, but
this should be considered an implementation detail and not something
we can rely on.
This also gets rid of an unnecessary string conversion -- the set
already contains strings.
syntax: glob
*.elc
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.pyd
*.pyc
*.swp
*.prof
\#*\#
.\#*
tests/.coverage*
tests/annotated
tests/*.err
build
contrib/hgsh/hgsh
dist
doc/*.[0-9]
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
patches
mercurial/__version__.py
mercurial.egg-info
Output/Mercurial-*.exe
.DS_Store
tags
cscope.*
i18n/hg.pot
locale/*/LC_MESSAGES/hg.mo
# files installed with a local --pure build
mercurial/base85.py
mercurial/bdiff.py
mercurial/diffhelpers.py
mercurial/mpatch.py
mercurial/osutil.py
mercurial/parsers.py
syntax: regexp
^\.pc/
^\.(pydev)?project