Update Service_Messages.md

doc/mtproto/Service_Messages.md

@@ -69,7 +69,10 @@ pong#347773c5 msg_id:long ping_id:long = Pong;
 These messages do not require acknowledgments. A pong is transmitted only in response to a ping while a ping can be initiated by either side.
 
 ## Deferred Connection Closure + PING
+```
 ping_delay_disconnect#f3427b8c ping_id:long disconnect_delay:int = Pong;
+```
+
 Works like ping. In addition, after this is received, the server starts a timer which will close the current connection disconnect_delay seconds later unless it receives a new message of the same type which automatically resets all previous timers. If the client sends these pings once every 60 seconds, for example, it may set disconnect_delay equal to 75 seconds.
 
 ## Request to Destroy Session
@@ -151,4 +154,4 @@ This message does not require a response or an acknowledgement. If the container
 
 If no http_wait is present in container, default values max_delay=0 (milliseconds), wait_after=0 (milliseconds), and max_wait=25000 (milliseconds) are used.
 
-If the client’s ping of the server takes a long time, it may make sense to set max_delay to a value that is comparable in magnitude to ping time.
+If the client’s ping of the server takes a long time, it may make sense to set max_delay to a value that is comparable in magnitude to ping time.