shelve: mention FILE options in help

Shelve do normally take a list of files or patterns to shelve and the command
summary should thus show [FILE]...

Note: --delete is a bit special and interpret the parameters as a list of
shelve names. This change makes that even less obvious from the help. Too bad
- we can't please everyone.

hgext/shelve.py

@@ -632,7 +632,7 b' def unshelve(ui, repo, *shelved, **opts)'
            _('show patch')),
           ('', 'stat', None,
            _('output diffstat-style summary of changes'))] + commands.walkopts,
-         _('hg shelve [OPTION]...'))
+         _('hg shelve [OPTION]... [FILE]...'))
 def shelvecmd(ui, repo, *pats, **opts):
     '''save and set aside changes from the working directory