Add unbreaking + mending (+infinity) to the Demonic Sword/Magic Bow

The sword/bow are only obtainable from Nightmare Boss/Legendary Dungeon crates at a less than 1% chance for each. These are meant to be the most valuable items in the gamemode or at least close to it (that's my understanding at least). All of the other Legendary items (armor, tools) have Unbreaking + Mending, but not the sword/bow. Given the extreme rarity of these items, I tend to think that if you obtain them, they should be durable and last you the rest of the season as long as you're able to avoid dying with them. In terms of the bow, it's important to consider that mending + infinity are mutually exclusive. You can put both on the same item with plugins/commands, but not with vanilla enchanting. For that reason I tend to think the bow should have both. This would also put the legendary items closer in line to what's in the current lootbox (custom sword/bow that do have unbreaking/mending/infinity)