Allow dungeons to destroy cobble and mossycobble

mods/MAPGEN/mcl_dungeons/init.lua

@@ -200,8 +200,9 @@ minetest.register_on_generated(function(minp, maxp)
 						local p_pos = area:index(tx, ty, tz)
 
 						-- Do not overwrite nodes with is_ground_content == false (e.g. bedrock)
+						-- Exceptions cobblestone and moss stone so neighborings dungeons nicely connect to each other
 						local name = minetest.get_name_from_content_id(data[p_pos])
-						if minetest.registered_nodes[name].is_ground_content then
+						if name == "mcl_core:cobble" or name == "mcl_core:mossycobble" or minetest.registered_nodes[name].is_ground_content then
 							-- Floor
 							if ty == y then
 								if math.random(1,4) == 1 then