Retire winstacker: remove doc ref

Winstackers project has been retired
- https://review.opendev.org/c/openstack/governance/+/886880

this commit removes doc ref of this project.

Depends-On: https://review.opendev.org/c/openstack/os-win/+/894411
Depends-On: https://review.opendev.org/c/openstack/compute-hyperv/+/894412
Depends-On: https://review.opendev.org/c/openstack/networking-hyperv/+/894413
Depends-On: https://review.opendev.org/c/openstack/oswin-tempest-plugin/+/894414
Change-Id: Ic014c92b9bef7327895479b1fcd8a8fcfbac82bf

tools/www-generator.py

@@ -453,6 +453,7 @@ _RETIRED_REPOS = [
     'openstack/anchor',
     'openstack/bandit',
     'openstack/castellan-ui',
+    'openstack/compute-hyperv',
     'openstack/congress',
     'openstack/congress-dashboard',
     'openstack/congress-tempest-plugin',
@@ -471,6 +472,7 @@ _RETIRED_REPOS = [
     'openstack/monasca-transform',
     'openstack/mox3',
     'openstack/networking-calico',
+    'openstack/networking-hyperv',
     'openstack/networking-l2gw',
     'openstack/networking-midonet',
     'openstack/networking-onos',
@@ -495,6 +497,8 @@ _RETIRED_REPOS = [
     'openstack/os-acc',
     'openstack/os-cloud-config',
     'openstack/oslosphinx',
+    'openstack/os-win',
+    'openstack/oswin-tempest-plugin',
     'openstack/paunch',
     'openstack/patrole',
     'openstack/python-ceilometerclient',