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: Ib5e3121d9f9ad7a89696157ae4b315bc3edf8657
Story: #2002586
Task: #24314

.zuul.yaml

@@ -4,8 +4,8 @@
       - periodic-stable-jobs-neutron
       - openstack-python-jobs-neutron
       - openstack-python35-jobs-neutron
-      - release-notes-jobs
-      - publish-openstack-sphinx-docs
+      - release-notes-jobs-python3
+      - publish-openstack-docs-pti
     check:
       jobs:
         - neutron-fwaas-networking-midonet-cross-py35:
@@ -15,7 +15,7 @@
             required-projects:
               - openstack/neutron
 
-        - build-openstack-sphinx-docs:
+        - openstack-tox-docs:
             required-projects:
               - openstack/neutron
         - legacy-neutron-fwaas-v2-dsvm-tempest
@@ -36,7 +36,7 @@
             required-projects:
               - openstack/neutron
 
-        - build-openstack-sphinx-docs:
+        - openstack-tox-docs:
             required-projects:
               - openstack/neutron
         - legacy-neutron-fwaas-v2-dsvm-tempest