Fixed #15395 -- Documented the modules/import paths for the various decorators...

Fixed #15395 -- Documented the modules/import paths for the various decorators in `django.views.decorators`. Thanks to slinkp for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15671 bcc190cf-cafb-0310-a4f2-bffc1f526a37