incorporate Akasurde PR feedback

lib/ansible/plugins/doc_fragments/openstack.py

@@ -24,7 +24,8 @@ class ModuleDocFragment(object):
       - Dictionary containing auth information as needed by the cloud's auth
         plugin strategy. For the default I(password) plugin, this would contain
         I(auth_url), I(username), I(password), I(project_name) and any
-        information about domains if the cloud supports them. For other plugins,
+        information about domains (for example, I(os_user_domain_name) or I(os_project_domain_name)) if the cloud supports them.
+        For other plugins,
         this param will need to contain whatever parameters that auth plugin
         requires. This parameter is not needed if a named cloud is provided or
         OpenStack OS_* environment variables are present.