added link in prepare-buy-reservation.md

Author: bandersmsft

articles/cost-management-billing/reservations/prepare-buy-reservation.md

@@ -95,6 +95,7 @@ You can purchase reservations from Azure portal, APIs, PowerShell, CLI. Read the
 - [Microsoft Fabric](fabric-capacity.md)
 - [Microsoft Sentinel - Pre-Purchase](../../sentinel/billing-pre-purchase-plan.md?toc=/azure/cost-management-billing/reservations/toc.json)
 - [Nutanix on Azure BareMetal](nutanix-bare-metal.md)
+- [Red Hat OpenShift](prepay-red-hat-openshift.md)
 - [SAP HANA Large Instances](prepay-hana-large-instances-reserved-capacity.md)
 - [Software plans](/azure/virtual-machines/linux/prepay-suse-software-charges?toc=/azure/cost-management-billing/reservations/toc.json)
 - [SQL Database](/azure/azure-sql/database/reserved-capacity-overview?toc=/azure/cost-management-billing/reservations/toc.json)