WORLDGUARD-3692 - Reported by mibby

1.9 introduced new tipped arrows, arrows with potion effects when hit. Unfortunately this means you can't block certain potions entirely since players could just hit themselves with the custom arrow type. (i.e. using an arrow of invisibility)

gameplay:
    block-potions:
    - invisibility

Requesting an option to be able to block specific tipped arrows, to fully block a potion type. :)