Update enchanted tools with outdated digging times

Because of the way digging times is implemented in Mineclone2, it is
possible for the digging times of efficiency enchanted tools to become
outdated.

This fixes that by automatically updating the tools tool_capabilities
after each time the tool is used.

mods/ITEMS/mcl_enchanting/engine.lua

@@ -219,6 +219,43 @@ function mcl_enchanting.enchantments_snippet(_, _, itemstack)
 	end
 end
 
+-- Returns after_use callback function for enchanted items.  The after_use
+-- callback is used to check the tool_capabilities of enchanted tools to update
+-- old enchanted tools with outdated digtimes in their tool_capabilities.
+--
+-- This is neccessary for digging times of tools to be in sync when MineClone2
+-- or mods change add new hardness values for nodes or when existing hardness
+-- values are changed.
+local function get_after_use_callback(itemdef)
+	if itemdef.after_use then
+		-- If the tool already has an after_use, make sure to call that
+		-- one too.
+		return function(itemstack, user, node, digparams)
+			itemdef.after_use(itemstack, user, node, digparams)
+
+			local enchantments = mcl_enchanting.get_enchantments(itemstack)
+			local level = enchantments.efficiency
+			if level then
+				mcl_enchanting.enchantments.efficiency.on_enchant(itemstack, level)
+			end
+		end
+	end
+
+	-- If the tool does not have after_use, add wear to the tool as if no
+	-- after_use was registered.
+	return function(itemstack, user, node, digparams)
+		if not minetest.is_creative_enabled(user) then
+			itemstack:add_wear(digparams.wear)
+		end
+
+		local enchantments = mcl_enchanting.get_enchantments(itemstack)
+		local level = enchantments.efficiency
+		if level then
+			mcl_enchanting.enchantments.efficiency.on_enchant(itemstack, level)
+		end
+	end
+end
+
 function mcl_enchanting.initialize()
 	local register_tool_list = {}
 	local register_item_list = {}
@@ -236,6 +273,7 @@ function mcl_enchanting.initialize()
 			new_def.groups.enchanted = 1
 			new_def.texture = itemdef.texture or itemname:gsub("%:", "_")
 			new_def._mcl_enchanting_enchanted_tool = new_name
+			new_def.after_use = get_after_use_callback(itemdef)
 			local register_list = register_item_list
 			if itemdef.type == "tool" then
 				register_list = register_tool_list