Update toc.yml

Author: shsagir

articles/cost-management-billing/reservations/toc.yml

@@ -39,7 +39,7 @@
     - name: Databricks
       href: reservation-discount-databricks.md
     - name: Data Explorer
-      href: understand-azure-data-explorer-reservation-charges.md
+      href: /azure/data-explorer/pricing-reservation-discount?toc=/azure/cost-management-billing/reservations/toc.json
     - name: Dedicated Hosts
       href: billing-understand-dedicated-hosts-reservation-charges.md
     - name: Defender for Cloud - Prepurchase