resolve: report no argument warning using a hint
With this change resolve and revert produce consistent output when run with no
arguments:
$ hg resolve
abort: no files or directories specified
(use --all to remerge all files)
$ hg revert
abort: no files or directories specified
(use --all to revert all files)
Mercurial's documentation is kept in reStructuredText format, which is
a simple plain text format that's easy to read and edit:
http://docutils.sourceforge.net/rst.html
It's also convertible to a variety of other formats including standard
UNIX man page format and HTML. You'll need to install Docutils:
http://docutils.sourceforge.net/
Use the Makefile in this directory to generate the man and HTML pages.