remove old Fx <112 compatibility rules

chrome/window_control_placeholder_support.css

@@ -80,11 +80,9 @@ See the above repository for updates as well as full license text. */
   :root[sizemode="fullscreen"] #TabsToolbar > .titlebar-buttonbox-container:last-child,
   :root[sizemode="fullscreen"] #window-controls{ right: unset; }
   .titlebar-buttonbox-container{
-    -moz-box-ordinal-group: 0 !important; /* Fx <112 compatibility */
     order: -1 !important;
   }
   .titlebar-buttonbox{
-    -moz-box-direction: reverse; /* Fx <112 compatibility */
     flex-direction: row-reverse;
   }
 }