Issue #23125: Update nose project page link.

Reported by Damien Marié.

Doc/library/unittest.rst

@@ -51,7 +51,7 @@ test runner
       Kent Beck's original paper on testing frameworks using the pattern shared
       by :mod:`unittest`.
 
-   `Nose <http://code.google.com/p/python-nose/>`_ and `py.test <http://pytest.org>`_
+   `Nose <https://nose.readthedocs.org/en/latest/>`_ and `py.test <http://pytest.org>`_
       Third-party unittest frameworks with a lighter-weight syntax for writing
       tests.  For example, ``assert func(10) == 42``.