Show product WC Stock availability on the single product page

/* Show product WC Stock availability on the single product page */
add_filter('woocommerce_get_availability', 'custom_get_availability', 1, 2);
function custom_get_availability($availability, $product) {
  if ($availability['availability'] == '') {
    $availability['availability'] = __('In Stock', 'woocommerce');
  }
  return $availability;
}