Merge pull request #306029 from Artturin/gnomeplatfor

gnomeExtensions: Set platforms

pkgs/desktops/gnome/extensions/buildGnomeExtension.nix

···
       longDescription = description;
       homepage = link;
       license = lib.licenses.gpl2Plus; # https://wiki.gnome.org/Projects/GnomeShell/Extensions/Review#Licensing
+      platforms = lib.platforms.linux;
       maintainers = with lib.maintainers; [ ];
     };
     passthru = {