Add signal comment

src/Vehicle/Vehicle.h

@@ -621,6 +621,7 @@ public:
     ///     @param component Component to send to
     ///     @param command MAV_CMD to send
     ///     @param showError true: Display error to user if command failed, false:  no error shown
+    /// Signals: mavCommandResult on success or failure
     void sendMavCommand(int component, MAV_CMD command, bool showError, float param1 = 0.0f, float param2 = 0.0f, float param3 = 0.0f, float param4 = 0.0f, float param5 = 0.0f, float param6 = 0.0f, float param7 = 0.0f);
 
     int firmwareMajorVersion(void) const { return _firmwareMajorVersion; }