Incorrect token mapping in attribute macros

[jonas-schievink]

I believe this happens because the tokens in the attribute use the same TokenIds as the tokens in the item, so they get remapped to the wrong tokens. The fix is to do the same thing as we do for MBE: shift all TokenIds up accordingly, so that they don't collide anymore.

[Veykril]

Trying to make myself more familiar with our macro machinery so I'll look into this.