add code to keep az gateway articel on ER TOC

Author: duongau

articles/expressroute/TOC.yml

@@ -58,9 +58,9 @@
     - name: Moving circuits from classic to Resource Manager
       href: expressroute-move.md
   - name: About ExpressRoute gateways
-    href: expressroute-about-virtual-network-gateways.md?toc=/azure/expressroute/toc.json
+    href: expressroute-about-virtual-network-gateways.md
   - name: About zone-redundant gateways for Availability Zones
-    href: ../vpn-gateway/about-zone-redundant-vnet-gateways.md
+    href: ../vpn-gateway/about-zone-redundant-vnet-gateways.md?toc=/azure/expressroute/toc.json
   - name: About ExpressRoute FastPath
     href: about-fastpath.md
   - name: About ExpressRoute Direct