tag: warn users about tag/branch possible name conflicts
As reported recently, Mercurial users can easily find confusion when
using a common name for a tag and a branch. It seems reasonable to warn
them about this potential outcome, to avoid that "surprise".
* Explain briefly the issue in "hg help tag"
* Warn when tagging a revision
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
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