Stairs: Add aliases needed due to new pine wood name

mods/stairs/init.lua

@@ -7,6 +7,12 @@
 stairs = {}
 
 
+-- Register aliases for new pine node names
+
+minetest.register_alias("stairs:stair_pinewood", "stairs:stair_pine_wood")
+minetest.register_alias("stairs:slab_pinewood", "stairs:slab_pine_wood")
+
+
 -- Get setting for replace ABM
 
 local replace = minetest.setting_getbool("enable_stairs_replace_abm")