introduce new RequirementError (issue2649)
This improves the misleading error message
$ hg identify
abort: there is no Mercurial repository here (.hg not found)!
to the more explicit
$ hg identify
abort: requirement 'fake' not supported!
for all commands in commands.optionalrepo, which includes the identify
and serve commands in particular.
This is for the case when a new entry in .hg/requires will be defined
in a future Mercurial release.
syntax: glob
*.elc
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.pyd
*.pyc
*.pyo
*$py.class
*.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