refactor(waybar): register owned modules

configs/nixos/modules/desktop/apps/steam.nix

@@ -2,6 +2,7 @@
   config,
   lib,
   pkgs,
+  util,
   ...
 }:
 # Steam game launcher and runtime integration.
@@ -26,7 +27,7 @@
 
     registry.window-icon.${config.networking.hostName}.steam = {
       class = "[Ss]team";
-      icon = "f1b6";
+      icon = util.glyph "f1b6";
     };
   };
 }