add a breadcrumb toc file for Network Watcher

Author: halkazwini

articles/network-watcher/breadcrumb/toc.yml

@@ -0,0 +1,8 @@
+items:
+- name: Azure
+  tocHref: /azure/
+  topicHref: /azure/index
+  items:
+  - name: Network Watcher
+    tocHref: /azure/virtual-machines/extensions/
+    topicHref: /azure/network-watcher/index

docfx.json

@@ -349,7 +349,8 @@
         "articles/messaging-services/*": true,
         "articles/defender-for-cloud/*": true,
         "articles/azure-monitor/*": true,
-        "articles/key-vault/*": true
+        "articles/key-vault/*": true,
+        "articles/network-watcher/*": true
       },
       "archive_url": {
         "articles/iot-edge/*": "/previous-versions/azure/iot-edge/"