now that forge PR is in, restore real icons.

🎉 🎉 🎉 🎉 🎉

As of latest commit, all that remains is the logic here:

which should just be a modified version of the vanilla code in MapItemRenderer.

However, I'm too lazy to do it right at this moment, and I also don't know what icon corresponds to what feature ID.

So if anyone wants to do it before I do go right ahead.