Added 'invalid message' error.

manual/manual.typ

@@ -17,13 +17,18 @@
 )
 
 = Messages
+=== Server
+```json
+{"e": 0, "info": "Invalid message"}
+```
+
 == Heartbeat
 === Server
 - ```json
 {"c": "ping"}
 ```<ping>
 - ```json
-{"e": 0, "info": "Pong missed"}
+{"e": 1, "info": "Pong missed"}
 ```<pongmissed>
 
 === Device
@@ -55,13 +60,13 @@
 {"c": "auth_ok"}
 ```<auth_ok>
 - ```json
-{"e": 1, "info": "Invalid packet, wrong ID."}
+{"e": 2, "info": "Invalid packet, wrong ID."}
 ```<auth_error_id>
 - ```json
-{"e": 2, "info": "Invalid signature."} // the info doesn't matter
+{"e": 3, "info": "Invalid signature."} // the info doesn't matter
 ```<auth_error_sig>
 - ```json
-{"e": 3, "info": "Logged in at other place."} // the info doesn't matter
+{"e": 4, "info": "Logged in at other place."} // the info doesn't matter
 ```<auth_error_takeover>
 
 === Device