Indent statement in docs function (#3910)

docs/userguide/workers.rst

@@ -1159,7 +1159,7 @@ for example one that reads the current prefetch count:
 
     @inspect_command
     def current_prefetch_count(state):
-    return {'prefetch_count': state.consumer.qos.value}
+        return {'prefetch_count': state.consumer.qos.value}
 
 
 After restarting the worker you can now query this value using the