gnomeExtensions.screenshot-tool: Fix paths

Fixes #136112.

pkgs/desktops/gnome/extensions/extensionPatches.nix

···
     '';
   });
 
+  "[e-mail]" = super."[e-mail]".overrideAttrs (old: {
+    # Requires gjs
+    # https://github.com/NixOS/nixpkgs/issues/136112
+    postPatch = ''
+      for file in *.js; do
+        substituteInPlace $file --replace "gjs" "${gjs}/bin/gjs"
+      done
+    '';
+  });
+
 }