Fix __repr__ in Waypoint

Beforehand, __repr__ in Waypoint called __repr__ of
self.location_ground. However, LocationGround only had __str__. I
changed repr(self.location_ground) to str(self.location_ground)

modules/waypoint.py

@@ -51,4 +51,4 @@ def __repr__(self) -> str:
         """
         String representation
         """
-        return f"LocationGroundAndAltitude: {repr(self.location_ground)}, altitude: {self.altitude}"
+        return f"LocationGroundAndAltitude: {str(self.location_ground)}, altitude: {self.altitude}"