stones: don't drop cobble, drop it self instead

nodes.lua

@@ -341,7 +341,7 @@ minetest.register_node("caverealms:stone_with_moss", {
 	tiles = {"default_cobble.png^caverealms_moss.png", "default_cobble.png", "default_cobble.png^caverealms_moss_side.png"},
 	is_ground_content = true,
 	groups = {cracky=3},
-	drop = 'default:cobble',
+	drop = 'caverealms:stone_with_moss',
 	sounds = default.node_sound_dirt_defaults({
 		footstep = {name="default_grass_footstep", gain=0.25},
 	}),
@@ -353,7 +353,7 @@ minetest.register_node("caverealms:stone_with_lichen", {
 	tiles = {"default_cobble.png^caverealms_lichen.png", "default_cobble.png", "default_cobble.png^caverealms_lichen_side.png"},
 	is_ground_content = true,
 	groups = {crumbly=3},
-	drop = 'default:cobble',
+	drop = 'caverealms:stone_with_lichen',
 	sounds = default.node_sound_dirt_defaults({
 		footstep = {name="default_grass_footstep", gain=0.25},
 	}),
@@ -365,7 +365,7 @@ minetest.register_node("caverealms:stone_with_algae", {
 	tiles = {"default_cobble.png^caverealms_algae.png", "default_cobble.png", "default_cobble.png^caverealms_algae_side.png"},
 	is_ground_content = true,
 	groups = {cracky=3},
-	drop = 'default:cobble',
+	drop = 'caverealms:stone_with_algae',
 	sounds = default.node_sound_dirt_defaults({
 		footstep = {name="default_grass_footstep", gain=0.25},
 	}),