How to Hide the "WP Add Active Class To Menu Item" Admin Menu

function plt_hide_wp_add_active_class_to_menu_item_menus() {
	//Hide the "Settings → WP Add Active Class To Menu Item" menu.
	remove_submenu_page('options-general.php', 'wp_add_active_class_to_menu_item_dashboard');
}

add_action('admin_menu', 'plt_hide_wp_add_active_class_to_menu_item_menus', 11);

Where do I put this code?