[Bug fix] Billing coupons (#18585)

* Add reusable for coupon expiration

* Incorporate reviewer feedback

Co-authored-by: Laura Coursen <lecoursen@github.com>

Co-authored-by: Laura Coursen <lecoursen@github.com>

Author: ethanpalm

content/github/setting-up-and-managing-billing-and-payments-on-github/redeeming-a-coupon.md

@@ -14,6 +14,8 @@ topics:
 
 {% data variables.product.product_name %} can't issue a refund if you pay for an account before applying a coupon. We also can't transfer a redeemed coupon or give you a new coupon if you apply it to the wrong account. Confirm that you're applying the coupon to the correct account before you redeem a coupon.
 
+{% data reusables.dotcom_billing.coupon-expires %}
+
 You cannot apply coupons to paid plans for {% data variables.product.prodname_marketplace %} apps.
 
 ### Redeeming a coupon for your personal account

content/github/setting-up-and-managing-billing-and-payments-on-github/removing-a-payment-method.md

@@ -15,6 +15,8 @@ topics:
 
 If you're paying for your {% data variables.product.product_name %} subscription with a coupon, and you aren't using your payment method for any [other paid features or products](/articles/about-billing-on-github) on {% data variables.product.product_name %}, you can remove your credit card or PayPal information.
 
+{% data reusables.dotcom_billing.coupon-expires %}
+
 {% tip %}
 
 **Tip:** If you [downgrade your account to a free product](/articles/downgrading-your-github-subscription) and you don't have subscriptions for any other paid features or products, we'll automatically remove your payment information.

data/reusables/dotcom_billing/coupon-expires.md

@@ -0,0 +1 @@
+If you use a coupon to pay for a subscription, when the coupon expires, your payment method will be charged the full cost of your subscription. If you do not have a saved payment method, your account will be downgraded to {% data variables.product.prodname_free_user %} for user accounts or {% data variables.product.prodname_free_team %} for organizations.