docs: Fix extlinks for updated sphinx

The slug parameter is now required in the link f-string.

doc/source/conf.py

@@ -122,10 +122,10 @@
 }
 
 extlinks = {
-    f"{project}-doc": (f"https://docs.openstack.org/{project}/{current_series}/", "%s documentation")
+    f"{project}-doc": (f"https://docs.openstack.org/{project}/{current_series}/%s", "%s documentation")
     for project in extlinks_projects
 }
-extlinks["skc-doc"] = (f"https://stackhpc-kayobe-config.readthedocs.io/en/stackhpc-{current_series}/", "%s documentation")
-extlinks["kayobe-renos"] = (f"https://docs.openstack.org/releasenotes/kayobe/{current_series}.html", "%s release notes")
-extlinks["kolla-ansible-renos"] = (f"https://docs.openstack.org/releasenotes/kolla-ansible/{current_series}.html", "%s release notes")
-extlinks["ceph-doc"] = (f"https://docs.ceph.com/en/{ceph_series}/", "%s documentation")
+extlinks["skc-doc"] = (f"https://stackhpc-kayobe-config.readthedocs.io/en/stackhpc-{current_series}/%s", "%s documentation")
+extlinks["kayobe-renos"] = (f"https://docs.openstack.org/releasenotes/kayobe/{current_series}.html%s", "%s release notes")
+extlinks["kolla-ansible-renos"] = (f"https://docs.openstack.org/releasenotes/kolla-ansible/{current_series}.html%s", "%s release notes")
+extlinks["ceph-doc"] = (f"https://docs.ceph.com/en/{ceph_series}/%s", "%s documentation")