Add api ref links for snapshots and volume types clients

This patch is just to add some api ref links for snapshots and volume
types clients.

Change-Id: I3ed05d65d61c8ff11b3dd8d993db2a8c12ad38ff
diff --git a/tempest/lib/services/volume/v3/snapshots_client.py b/tempest/lib/services/volume/v3/snapshots_client.py
index 298925a..f79bcd8 100644
--- a/tempest/lib/services/volume/v3/snapshots_client.py
+++ b/tempest/lib/services/volume/v3/snapshots_client.py
@@ -176,11 +176,12 @@
         return rest_client.ResponseBody(resp, body)
 
     def update_snapshot_metadata_item(self, snapshot_id, id, **kwargs):
-        """Update metadata item for the snapshot."""
-        # TODO(piyush): Current api-site doesn't contain this API description.
-        # After fixing the api-site, we need to fix here also for putting the
-        # link to api-site.
-        # LP: https://bugs.launchpad.net/openstack-api-site/+bug/1529064
+        """Update metadata for the snapshot for a specific key.
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        https://developer.openstack.org/api-ref/block-storage/v3/#update-a-snapshot-s-metadata-for-a-specific-key
+        """
         put_body = json.dumps(kwargs)
         url = "snapshots/%s/metadata/%s" % (snapshot_id, id)
         resp, body = self.put(url, put_body)
diff --git a/tempest/lib/services/volume/v3/types_client.py b/tempest/lib/services/volume/v3/types_client.py
index 6d9d03a..aac9129 100644
--- a/tempest/lib/services/volume/v3/types_client.py
+++ b/tempest/lib/services/volume/v3/types_client.py
@@ -91,9 +91,9 @@
     def list_volume_types_extra_specs(self, volume_type_id, **params):
         """List all the volume_types extra specs created.
 
-        TODO: Current api-site doesn't contain this API description.
-        After fixing the api-site, we need to fix here also for putting
-        the link to api-site.
+        For a full list of available parameters, please refer to the official
+        API reference:
+        https://developer.openstack.org/api-ref/block-storage/v3/#show-all-extra-specifications-for-volume-type
         """
         url = 'types/%s/extra_specs' % volume_type_id
         if params: