title: Get refunded orders and refunded order items details in Woocommerce 3
body: <p>I see when I look at an order it will show the specific item that was refunded if the whole order wasn't. </p>
  
  <p>Is there a way to find using the <code>WC_Order_Item_Product</code> if an item was refunded?  Also, is there a way to get the discount amount that shows up below the item in the order view?  </p>
  
  <p>I'm currently doing it manually but if there is a function for it already, I would rather use it.</p>