WooCommerce - Simple show stock shortcode

<?php
// simple show stock shortcode - only works on product page
// usage: Only [show_stock] available!
// code goes in functions.php for your child theme
add_shortcode('show_stock', 'show_stock');
function show_stock() {
  global $product;
  return (int) $product->get_stock_quantity(); // for WC 3.x onwards
}