update toc

Author: rboucher

articles/azure-monitor/toc.yml

@@ -98,6 +98,8 @@
       href: platform/data-security.md
     - name: Customer-managed keys
       href: platform/customer-managed-keys.md
+    - name: Private Link networking
+      href: platform/private-link-security.md
     - name: Personal log data handling
       href: platform/personal-data-mgmt.md
     - name: Application data collection, retention, and storage