PEP 101: mention "Current Pre-release Testing Version" page.

pep-0101.txt

@@ -612,6 +612,31 @@ None of the web site updates are automated by release.py.
       Note: Python x.y.m has been superseded by
       `Python x.y.n </download/releases/x.y.n/>`_.
 
+  - Update the "Current Pre-release Testing Versions web page".
+
+    There's a page that lists all the currently-in-testing versions
+    of Python:
+
+        https://www.python.org/download/pre-releases/
+
+    Every time you make a release, one way or another you'll
+    have to update this page:
+
+    - If you're releasing a version before *x.y.0*,
+      or *x.y.z release candidate N,*
+      you should add it to this page, removing the previous pre-release
+      of version *x.y* as needed.
+
+    - If you're releasing *x.y.z final*, you need to remove the pre-release
+      version from this page.
+
+    This is in the "Pages" category on the Django-based website, and finding
+    it through that UI is kind of a chore.  However!  If you're already logged
+    in to the admin interface (which, at this point, you should be), Django
+    will helpfully add a convenient "Edit this page" link to the top of the
+    page itself.  So you can simply follow the link above, click on the
+    "Edit this page" link, and make your changes as needed.  How convenient!
+
   - Other steps (other update for new web site)??
 
 Now it's time to write the announcement for the mailing lists.  This is the