We definitely no longer support Python 2

I'm keeping that information in both the changes and upgrading documents
to increase the chances that people will notice it.

The imprecise "changes" statement predated the decision to drop Python 2
entirely and was spotted by Geoff.

doc/sphinx/whats-new/changes-6.2.rst

@@ -228,8 +228,7 @@ being, we still use :ref:`varnishtest(1)` for our own testing.
 Changes for developers and VMOD authors
 =======================================
 
-Python tools that generate code now prefer python 3 over python 2,
-when availabale.
+Python tools that generate code now require Python 3.
 
 .. _whatsnew_changes_director_api_2019_03:
 

doc/sphinx/whats-new/upgrading-6.2.rst

@@ -163,7 +163,7 @@ For developers and authors of VMODs and API clients
 Python 3.4 or later is now required to build Varnish, or use scripts
 installed along with Varnish, such as ``vmodtool.py`` to build VMODs
 or other Varnish artifacts. Python 2 is no longer supported, and this
-support will likely be dropped from stable branches too.
+support will likely be dropped in a future 6.0 LTS release too.
 
 The VRT API has been bumped to version 9.0. Changes include: