Entity: Add comments on likely new code

dGame/Entity.h

@@ -526,6 +526,8 @@ inline ComponentType* Entity::AddComponent(VaArgs... args) {
 	} else {
 		// In this case the block is already allocated and ready for use
 		// so we use a placement new to construct the component again as was requested by the caller.
+		// Placement new means we already have memory allocated for the object, so this just calls its constructor again.
+		// This is useful for when we want to create a new object in the same memory location as an old one.
 		new(componentToReturn) ComponentType(this, std::forward<VaArgs>(args)...);
 	}