Fixed #15134 -- Removed a duplicate TOC entry for modelforms docs. Thanks to Aryeh Leib Taurog for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15366 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/topics/index.txt

@@ -10,7 +10,6 @@ Introductions to all the key parts of Django you'll need to know:
    db/index
    http/index
    forms/index
-   forms/modelforms
    templates
    class-based-views
    generic-views-migration