Updated stuff, kotlin, fixed warning in xmonad config, idk what else

modules/dev/default.nix

@@ -8,6 +8,7 @@
     ./dhall.nix
     ./haskell
     ./fsharp.nix
+    ./kotlin.nix
     # ./racket.nix
     # ./elm.nix
 

modules/dev/kotlin.nix

@@ -0,0 +1,8 @@
+{ pkgs, ... }: {
+  home-manager.users.adrielus = {
+    home.packages = with pkgs; [
+      kotlin
+      gradle
+    ];
+  };
+}