[Plugin: WooCommerce] Adding "Backorder" label on product page

Hi all,

On the product list page, we can see that items are labelled “Out of stock” if we do not allow back-order on these product.

What if for certain product, which is already out of stock, but we allow backorder? How do we add a label “Allow backorder” on these products?

This is so that customer are aware on such, without having to click on each product only to realise that it is out of stock and they can only create backorder.

Thanks.