add TODO about optimizing character ray tracing

libraries/physics/src/CharacterGhostObject.cpp

@@ -69,6 +69,7 @@ bool CharacterGhostObject::rayTest(const btVector3& start,
         const btVector3& end,
         CharacterRayResult& result) const {
     if (_world && _inWorld) {
+        // TODO: we need to call btGhostObject::rayTest() here to reap the benefit of btGhostObject's optimizations
         _world->rayTest(start, end, result);
     }
     return result.hasHit();