Have mushroom spread abm use group:mushroom to spread not only default red and brown but all defined shrooms.
@@ -248,7 +248,7 @@ end
minetest.register_abm({
label = "Mushroom spread",
- nodenames = {"flowers:mushroom_brown", "flowers:mushroom_red"},
+ nodenames = {"group:mushroom"},
interval = 11,
chance = 150,
action = function(...)