Don't Keep Vanishing Items

Normally items with curse of vanishing don't disappear when the player dies with keep inventory enabled, essentially making the curse pointless on a world or server with keep inventory. This mod is simply one mixin that makes the items disappear even if keep inventory is enabled, making the curse actually a curse.

I am by no means an expert or even knowledgable about how mixins work, but in my own testing the mod seems to work fine, but no promises. :P