Update index.yml

Author: mbender-ms

articles/virtual-network-manager/index.yml

@@ -115,12 +115,12 @@ landingContent:
       - linkListType: overview
         links:
           - text: What is Virtual Network Verifier?
-            url: concept-virtual-network-verifier
+            url: concept-virtual-network-verifier.md
       - linkListType: how-to-guide
         links:
           - text: Configure event logs for Azure Virtual Network Manager
             url: how-to-configure-event-logs.md
       - linkListType: how-to-guide
         links: 
           - text: Verify resource reachability with Virtual Network Verifier
-            url: how-to-verify-reachability-with-virtual-network-verifier
+            url: how-to-verify-reachability-with-virtual-network-verifier.md