like the title says, adding a macroblock tag for macroblock sets.

As there isn't a proper platform for uploading macroblock sets rn a lot of people use IX for this. These macros are then individually listed as items alongside proper items. And given the size of some of these sets, it might make it slightly difficult to find what you're looking for if you want to find an item within a tag that the macroblock set also uses. Adding a macroblock tag would allow people looking for items to filter out the macros, and also allow vanilla mappers to find macro sets more easily.