AP_Mission: updated comment

altitude and lat/lng are all used

libraries/AP_Mission/AP_Mission.cpp

@@ -536,7 +536,7 @@ bool AP_Mission::mavlink_to_mission_cmd(const mavlink_mission_item_t& packet, AP
         break;
 
     case MAV_CMD_NAV_CONTINUE_AND_CHANGE_ALT:           // MAV ID: 30
-        copy_location = true;                           // only using alt
+        copy_location = true;                           // lat/lng used for heading lock
         cmd.p1 = packet.param1;                         // Climb/Descend
                         // 0 = Neutral, cmd complete at +/- 5 of indicated alt.
                         // 1 = Climb, cmd complete at or above indicated alt.
@@ -867,7 +867,7 @@ bool AP_Mission::mission_cmd_to_mavlink(const AP_Mission::Mission_Command& cmd,
         break;
 
     case MAV_CMD_NAV_CONTINUE_AND_CHANGE_ALT:           // MAV ID: 30
-        copy_location = true;                           //only using alt
+        copy_location = true;                           // lat/lng used for heading lock
         packet.param1 = cmd.p1;                         // Climb/Descend
                         // 0 = Neutral, cmd complete at +/- 5 of indicated alt.
                         // 1 = Climb, cmd complete at or above indicated alt.