fix heading for security

Author: asudbring

articles/virtual-network/toc.yml

@@ -222,7 +222,7 @@
     href: virtual-network-troubleshoot-connectivity-problem-between-vms.md
   - name: Troubleshoot virtual network deletion failures
     href: virtual-network-troubleshoot-cannot-delete-vnet.md
-- name: Security and compliance
+- name: Security
   items:
   - name: Azure Kubernetes network policies
     href: kubernetes-network-policies.md