AP_Mission: update NAV_DELAY comment that said wrong ID number

libraries/AP_Mission/AP_Mission.cpp

@@ -790,7 +790,7 @@ MAV_MISSION_RESULT AP_Mission::mavlink_int_to_mission_cmd(const mavlink_mission_
         cmd.p1 = packet.param1;                         // on/off. >0.5 means "on", hand-over control to external controller
         break;
 
-    case MAV_CMD_NAV_DELAY:                            // MAV ID: 94
+    case MAV_CMD_NAV_DELAY:                            // MAV ID: 93
         cmd.content.nav_delay.seconds = packet.param1; // delay in seconds
         cmd.content.nav_delay.hour_utc = packet.param2;// absolute time's hour (utc)
         cmd.content.nav_delay.min_utc = packet.param3;// absolute time's min (utc)
@@ -1222,7 +1222,7 @@ bool AP_Mission::mission_cmd_to_mavlink_int(const AP_Mission::Mission_Command& c
         packet.param1 = cmd.p1;                         // on/off. >0.5 means "on", hand-over control to external controller
         break;
 
-    case MAV_CMD_NAV_DELAY:                            // MAV ID: 94
+    case MAV_CMD_NAV_DELAY:                            // MAV ID: 93
         packet.param1 = cmd.content.nav_delay.seconds; // delay in seconds
         packet.param2 = cmd.content.nav_delay.hour_utc; // absolute time's day of week (utc)
         packet.param3 = cmd.content.nav_delay.min_utc; // absolute time's hour (utc)