Add recipe to craft clay block back into lumps

Added a recipe to craft a clay block back into 4 clay lumps.

mods/default/crafting.lua

@@ -507,6 +507,13 @@ minetest.register_craft({
 	}
 })
 
+minetest.register_craft({
+	output = 'default:clay_lump 4',
+	recipe = {
+		{'default:clay'},
+	}
+})
+
 minetest.register_craft({
 	output = 'default:brick',
 	recipe = {