[1.2.X] Fixed #14676 - Document that the removetags filter is case-sensitive....

[1.2.X] Fixed #14676 - Document that the removetags filter is case-sensitive. Thanks peterh32 for the report and elbarto for the patch.

Backport of r14925 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14926 bcc190cf-cafb-0310-a4f2-bffc1f526a37