Update toc.yml

Author: JasonWHowell

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

@@ -60,7 +60,7 @@
     - name: Synapse Analytics - Data warehouse
       href: reservation-discount-azure-sql-dw.md
     - name: Virtual machines
-      href: ../manage/understand-vm-reservation-charges?toc=/azure/cost-management-billing/reservations/toc.json
+      href: ../manage/understand-vm-reservation-charges.md?toc=/azure/cost-management-billing/reservations/toc.json
     - name: Virtual machine software
       href: understand-vm-software-reservation-discount.md
   - name: Windows and SQL costs not included