change filename in docs

docs/html/development/architecture/package-finding.rst

@@ -85,8 +85,8 @@ difference may simply be historical and may not actually be necessary.)
 
 Each of these commands also uses the ``PackageFinder`` class for pip's
 "self-check," (i.e. to check whether a pip upgrade is available). In this
-case, the ``PackageFinder`` instance is created by the ``outdated.py``
-module's ``pip_self_version_check()`` function.
+case, the ``PackageFinder`` instance is created by the
+``self_outdated_check.py`` module's ``pip_self_version_check()`` function.
 
 The ``PackageFinder`` class is responsible for doing all of the things listed
 in the :ref:`Overview <index-py-overview>` section like fetching and parsing