rebalancing for mending and anvils

For anvils, repair cost will be separate from enchanting cost, so if you were to combine an enchanted tool with an non-enchanted tool or ingots, the repair cost will always be a maximum of 3 levels no matter how much it will cost to combine it with another enchanted tool or book. And mending should not be obtainable from villagers or fishing.

What problems does this solve, first it makes repairing items with anvils become tangible and gives players a reason to obtain huge quantities of diamond, netherite and gold. Second it makes mending feel like a rare, special enchantment again and can give players a reason to explore their world. Third it makes mending not a requirement anymore, so that even if a player is not able to find a mending book, it will still be possible for them to keep their enchanted tools.