[1.1.X] Added hyperlinks for builtin template tags and filters to code samples in docs.

  
Implemented in javascript because doing it 'properly' is pretty much impossible with Sphinx and Pygments.
  
Refs #12249

Backport of [13135] from trunk


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@13137 bcc190cf-cafb-0310-a4f2-bffc1f526a37