help: filter out deprecated options with untranslated descriptions
When using a different language than English, deprecated options were only
removed from the output of `hg help anycmd` when "DEPRECATED" in the options
description was translated.
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.