Missing icons in F41

[Ron Yorston]

Using GNOME Shell on Wayland in Fedora 41 with Hicolor icons:

- GNOME Terminal displays the 'missing icon' icon instead of
  '+' and '-'.

Using GNOME Shell Classic on Wayland in Fedora 41 with either
Hicolor or Adwaita icons:

- Icecat has the 'unknown app' icon in the Window List.  (Actually,
  I don't think this is new in F41.)

Cheers,

Ron