Possible ordering issue in WorldScanner

Since it's chunk based, with an early return if it finds a certain number of locations, there might be some strange behavior.

For example, if you scan for ender_chest, and your current chunk has 64 ender chests at y=16 through y=20, it will only return those locations. This is an issue because those aren't necessarily the 64 closest ender chests. If the chunk immediately adjacent has some at your current y level, they'll be completely ignored.

I'm not sure how much this will actually happen in practice though.