Updating ToC

Author: v-jbasden

articles/azure-monitor/toc.yml

@@ -679,6 +679,8 @@ items:
           - name: Application Insights API summary
             displayName: SDK, API, custom events, custom metrics, trackevent, trackmetric, getmetric, trackrequest, trackexception, tracktrace, trackdependency
             href: app/api-custom-events-metrics.md
+          - name: Application Insights data model
+            href: app/data-model-complete.md
           - name: Connection strings
             href: app/sdk-connection-string.md
             displayName: connection string, instrumentation key