Add an endpoint for processing pay for order orders

docs/internal-developers/blocks/feature-flags-and-experimental-interfaces.md

@@ -43,6 +43,7 @@ The majority of our feature flagging is blocks, this is a list of them:
 -   Product Rating Counter ([PHP flag](https://github.com/woocommerce/woocommerce-blocks/blob/trunk/src/BlockTypesController.php#L229) | [webpack flag](https://github.com/woocommerce/woocommerce-blocks/blob/trunk/bin/webpack-entries.js#L71-L73))
 -   ⚛️ Add to cart ([JS flag](https://github.com/woocommerce/woocommerce-blocks/blob/dfd2902bd8a247b5d048577db6753c5e901fc60f/assets/js/atomic/blocks/product-elements/add-to-cart/index.ts#L26-L29)).
 -   Order Route ([PHP flag](https://github.com/woocommerce/woocommerce-blocks/blob/b4a9dc9334f82c09f533b0f88c947b5c34e4e546/src/StoreApi/RoutesController.php#L65-L67))
+-   Checkout Order Route ([PHP flag](https://github.com/woocommerce/woocommerce-blocks/blob/add/an-endpoint-for-process-pay-for-order-orders/src/StoreApi/RoutesController.php#L67))
 
 ## Features behind flags
 

src/StoreApi/Routes/V1/CartUpdateCustomer.php

@@ -7,7 +7,7 @@
 /**
  * CartUpdateCustomer class.
  *
- * Updates the customer billing and shipping address and returns an updated cart--things such as taxes may be recalculated.
+ * Updates the customer billing and shipping addresses, recalculates the cart totals, and returns an updated cart.
  */
 class CartUpdateCustomer extends AbstractCartRoute {
 	use DraftOrderTrait;