Hide "2/locked" as appropriate

Wraps the various item-purchase hints in `span` elements that hide if you have everything in the set, so if you've already purchased e.g. every background in a set, you don't still see the "2/locked" bit.

~~Does *not* yet fix the issue where hairstyles still show as unpurchased even when bought. Depending on if/when this gets merged, I'll try to figure out what's going on there and add the fix to this PR.~~ Now also fixes the problem where you could repeatedly purchase the base hairstyle set.