[1.0.X] A few minor wording, whitespace, punctuation, and link changes for the...

[1.0.X] A few minor wording, whitespace, punctuation, and link changes for the middleware documentation.

Backport of r9833 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@9834 bcc190cf-cafb-0310-a4f2-bffc1f526a37