[1.0.X] Added django.contrib.markup to the docs contents page. Thanks, Marc Fargas.

Refs #9237.

Backport of r9139 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9141 bcc190cf-cafb-0310-a4f2-bffc1f526a37