Villager Fix

This is my idea for a Villager fix.

1. Remove trades where villagers sell emeralds to the player. This fixes so the user can no longer infinitely farm a crop for emeralds.

With Emeralds no longer obtainable through trades, they become a scarce resource again. (Unless a change is made, which is part 2 of this suggestion.

2. To ensure players can still engage with villager trading, emeralds should become more accessible in the world. I suggest:
* Expanding the types of locations where emeralds can spawn, rather than limiting them to mountains.
* Increasing the quantity of emeralds per ore vein to make them more obtainable.

Extra: Maybe start using emerald blocks for certain trades you've seemed to want to nerf in the past like mending.