AP_Mount: minor spelling fix

libraries/AP_Mount/AP_Mount_Backend.cpp

@@ -224,7 +224,7 @@ bool AP_Mount_Backend::calc_angle_to_location(const struct Location &target, Vec
 
     // pan calcs
     if (calc_pan) {
-        // calc absolute heading and then onvert to vehicle relative yaw
+        // calc absolute heading and then convert to vehicle relative yaw
         angles_to_target_rad.z = atan2f(GPS_vector_x, GPS_vector_y);
         if (relative_pan) {
             angles_to_target_rad.z = wrap_PI(angles_to_target_rad.z - AP::ahrs().yaw);