Minor docstring changes

services/workflow/src/workflow/server.py

@@ -54,7 +54,8 @@ class WorkflowRestService:
         List the workflow requests that we know about.
 
         Audience: front-end
-        :return:
+
+        :return: None
         """
         return self.request.info.all_workflows()
 
@@ -64,7 +65,8 @@ class WorkflowRestService:
         Look up a workflow request
 
         Audience: front-end
-        :return:
+
+        :return: None
         """
         return self.request.context