[1.2.X] Documented options accepted by the runfcgi management command.

Also, modified our custom management command option docs xref parser
to also process those without a ``--`` prefix. --  Refs #14398.

Backport of [14361] from trunk

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14363 bcc190cf-cafb-0310-a4f2-bffc1f526a37