switch documentation job to new PTI

This is a mechanically generated patch to switch the documentation
jobs to use the new PTI versions of the jobs as part of the
python3-first goal.

See the python3-first goal document for details:
https://governance.openstack.org/tc/goals/stein/python3-first.html

Change-Id: I16f646207f291b8d81b527d60c9bd68a69e8fb25
Story: #2002586
Task: #24341

zuul.d/layout.yaml

@@ -4,8 +4,8 @@
       - tripleo-multinode-baremetal-minimal
       - tripleo-multinode-container-minimal
       - tripleo-multinode-branchful
-      - publish-openstack-sphinx-docs
-      - release-notes-jobs
+      - publish-openstack-docs-pti
+      - release-notes-jobs-python3
     check:
       jobs:
         - tripleo-ci-centos-7-3nodes-multinode: