Copter: fixed comment on get_pilot_desired_yaw_rate

ArduCopter/Attitude.cpp

@@ -36,9 +36,9 @@ void Copter::get_pilot_desired_lean_angles(float roll_in, float pitch_in, float
     pitch_out = pitch_in;
 }
 
-// get_pilot_desired_heading - transform pilot's yaw input into a desired heading
-// returns desired angle in centi-degrees
-// To-Do: return heading as a float?
+// get_pilot_desired_heading - transform pilot's yaw input into a
+// desired yaw rate
+// returns desired yaw rate in centi-degrees per second
 float Copter::get_pilot_desired_yaw_rate(int16_t stick_angle)
 {
     // convert pilot input to the desired yaw rate