Fixed entry for What is

Author: flang-msft

articles/partner-solutions/datadog/toc.yml

@@ -2,7 +2,7 @@
   href: index.yml
 - name: Overview
   items:
-  - name: What is Datadog?
+  - name: What is Datadog - An Azure Native ISV Service?
     href: overview.md
     displayName: Datadog, Monitoring
 - name: Quickstarts