fix

doc/30-services.md

@@ -109,7 +109,8 @@ from example_interfaces.srv import AddTwoInts
 
 class AddTwoIntsServer(Node):
     def __init__(self):
-        super().__init__('add_two_ints_server_py')
+        # 节点名(实际本仓库无 _py 后缀,launch 也不重命名)
+        super().__init__('add_two_ints_server')
         # create_service(srv_type, srv_name, callback)
         # callback 签名: callback(request, response) -> response
         self.srv = self.create_service(
@@ -167,7 +168,7 @@ private:
 ```python
 class Client(Node):
     def __init__(self):
-        super().__init__('add_two_ints_client_py')
+        super().__init__('add_two_ints_client')
         self.client = self.create_client(AddTwoInts, 'add_two_ints')
 
         # 阻塞等服务端上线(1s 超时,循环等)