Apps: Replace nixd with nil

.vscode/settings.json

@@ -2,6 +2,6 @@
     "direnv.path.executable": "/run/current-system/sw/bin/direnv",
     "direnv.restart.automatic": true,
     "nix.enableLanguageServer": true,
-    "nix.serverPath": "/run/current-system/sw/bin/nixd",
+    "nix.serverPath": "/run/current-system/sw/bin/nil",
     "nix.formatterPath": "/run/current-system/sw/bin/nix fmt",
-}
+}

modules/apps/development.nix

@@ -20,6 +20,7 @@ in
     (lib.mkIf cfg.enable {
       aux.system = {
         packages = with pkgs; [
+          nil # Nix Language server: https://github.com/oxalica/nil
           nix-prefetch-scripts
         ];
         ui.flatpak = {