Fix overlay

overlays/default.nix

@@ -1,3 +1,7 @@
 { pkgs, ... }:
-[ ]
-#  [(import ./openttd-jgrpp) (import ./yarn-berry)]
+[
+  (final: prev: {
+    openttd-jgrpp = import ./openttd-jgrpp { inherit final prev; };
+    yarn-berry = import ./yarn-berry { inherit final prev; };
+  })
+]