Fixed a typo and added a bit more ReST markup to cache middleware docstring.
Fixed a typo and added a bit more ReST markup to cache middleware docstring.

--HG--
extra : convert_revision : svn%3Abcc190cf-cafb-0310-a4f2-bffc1f526a37/django/trunk%408387

adieu/django-nonrel,adieu/django-nonrel,adieu/django-nonrel