How to use promotable Boolean in Craft Commerce? I'm sure this is somewhere in Craft documentation but I cannot find anything on it. There is that checkbox in the product area that says "Promotable". I'm assuming this is so I can reference it later in the code (which is why I'm interested in this box), but I've browsed through the documentation and found nothing about it. The lack of questions about it on here makes me assume I just missed it. Could I get an explanation or a link? Thanks!
In Craft Commerce?


  promotable (true or false)
  Is this product and its variants able to be on sale or at a discount.


https://craftcommerce.com/docs/product-model#promotable