Corrected a markup error in the m2m inline docs.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11723 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/ref/contrib/admin/index.txt

@@ -1070,7 +1070,7 @@ Suppose we have the following models::
         members = models.ManyToManyField(Person, related_name='groups')
 
 If you want to display many-to-many relations using an inline, you can do
-so by defining an ``InlineModelAdmin`` object for the relationship.
+so by defining an ``InlineModelAdmin`` object for the relationship::
 
     class MembershipInline(admin.TabularInline):
         model = Group.members.through