Add combat enchantments for hoes

I really like the variety of melee weapons presented in this snapshot. Swords are of course the best weapon in most cases, but some mobs (such as skellies) are better to fight with axes, and some that you want to keep away (such as creepers) are better to fight with hoes.

However, once players start getting enchantments, they'll only use swords and axes because hoes have no combat-related enchantments at all. I think we should allow players to put Sharpness, Smite, and Bane of Athropods on hoes. However, considering the high attack speed and range of a hoe, we should limit players to a max of a level 3 enchantment. So if you try putting Sharpness IV or stronger on a hoe, it'll just cap at Sharpness III.