Fix NOTE in Azure CNI overlay docs

Author: wedaly

articles/aks/azure-cni-overlay.md

@@ -192,7 +192,7 @@ az aks update --name $clusterName \
 
 Since the cluster is already using a private CIDR for pods, you don't need to specify the `--pod-cidr` parameter and the Pod CIDR will remain the same.
 
-> [NOTE!]
+> [!NOTE]
 > When upgrading from Kubenet to CNI Overlay, the route table will no longer be required for pod routing. If the cluster is using a customer provided route table, the routes which were being used to direct pod traffic to the correct node will automatically be deleted during the migration operation. If the cluster is using a managed route table (the route table was created by AKS and lives in the node resource group) then that route table will be deleted as part of the migration.
 
 ## Dual-stack Networking (Preview)