How to Hide the "Disable REST API" Admin Menu

function plt_hide_disable_json_api_menus() {
	//Hide the "Settings → Disable REST API" menu.
	remove_submenu_page('options-general.php', 'disable_rest_api_settings');
}

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

Where do I put this code?