Add Toggle for Zombie Villager Discounts

Right now, curing a zombified villager gives a trade discount — but only partially, and it no longer drops everything down to 1 emerald like it used to. I’m suggesting a toggleable setting that would let players choose whether or not villagers can give full discounts down to 1 emerald after being cured. This would be perfect for players who want that old-school zombie curing benefit, but it would also let others keep the more balanced prices if they prefer.