updated toc

Author: bandersmsft

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

@@ -56,6 +56,10 @@
       href: manage-reserved-vm-instance.md#change-optimize-setting-for-reserved-vm-instances
     - name: Exchange and refund reservations
       href: exchange-and-refund-azure-reservations.md
+  - name: Report costs
+    items:
+    - name: View reservation transactions
+      href: view-reservation-purchase-refunds.md
   - name: Renew reservations
     items:
     - name: Renew a reservation