fix(devkit,ghostty): point to wrapped executable in ghostty desktop file

packages/devkit/ghostty.nix

@@ -2,7 +2,6 @@
   symlinkJoin,
   makeWrapper,
   pkgs,
-  lib,
   ghostty ? pkgs.ghostty,
   command ? null,
 }: let
@@ -36,9 +35,7 @@
 in
   symlinkJoin ({
       paths = [ghostty];
-
-      nativeBuildInputs = [makeWrapper];
-
+      nativeBuildInputs = [makeWrapper pkgs.coreutils];
       postBuild = ''
         wrapProgram $out/bin/ghostty \
           --add-flags '--theme=${theme}' ${
@@ -46,6 +43,9 @@ in
           then "--add-flags '-e' --add-flags '${command}'"
           else ""
         }
+        sed -i \
+          "s|Exec=.*|Exec=$out/bin/ghostty --gtk-single-instance=true|" \
+          $out/share/applications/com.mitchellh.ghostty.desktop
       '';
     }
     // {inherit (ghostty) name pname meta shell_integration terminfo;})