[1.0.X] Fixed #8768 -- Clarified that ugettext_lazy() results are unicode

proxies and can't be used as bytestrings.

Still a number of markup changes to be made in this file (and in this
changeset). That's intentional for now, since I'm going to rewrite the file
later this week.

Backport of r9168 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9174 bcc190cf-cafb-0310-a4f2-bffc1f526a37