check-seclevel: set module load policy to Python only
If we don't change this, the upcoming change to make the module
loading policy only load C modules will cause this script to fail if
run with CPython against an unbuilt source checkout.
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.