Fixed a few typos in the unittest2 docs introduced in [14139].

    To access this library, Django provides the

    ``django.utils.unittest`` module alias. If you are using Python

    2.7, or you have installed unittest2 locally, Django will mapt the

    alias to the installed version of the unittest library Otherwise,

    2.7, or you have installed unittest2 locally, Django will map the

    alias to the installed version of the unittest library. Otherwise,

    Django will use it's own bundled version of unittest2.

    To use this alias, simply use::

        from django.utils import unittest

    wherever you would historically used::

    wherever you would have historically used::

        import unittest