Make a warning more informative

Since we know what size was too large here, why not say it.

gdk/x11/gdkwindow-x11.c

@@ -3840,7 +3840,7 @@ gdk_x11_window_set_icon_list (GdkWindow *window,
       /* silently ignore overlarge icons */
       if (size + 2 + width * height > GDK_SELECTION_MAX_SIZE(display))
 	{
-	  g_warning ("gdk_window_set_icon_list: icons too large");
+	  g_warning ("gdk_window_set_icon_list: icon too large (%dx%d)", width, height);
 	  break;
 	}