Merge pull request #275722 from zhiyuanliang-ms/zhiyuanliang/migrate-fm-readme

Azure App Configuration - Migrate FeatureManagement-Dotnet github repo README to Microsoft.Learn

Author: JamesJBarnett

articles/azure-app-configuration/TOC.yml

@@ -316,9 +316,15 @@
     - name: Feature management
       items:
         - name: .NET
-          href: /dotnet/api/overview/azure/appconfiguration/featuremanagement
+          items: 
+            - name: Feature reference
+              href: ./feature-management-dotnet-reference.md
+            - name: API reference
+              href: /dotnet/api/overview/azure/appconfiguration/featuremanagement
         - name: Java Spring
-          href: https://azure.github.io/azure-sdk-for-java/springboot.html
+          items:
+            - name: API reference
+              href: https://azure.github.io/azure-sdk-for-java/springboot.html
     - name: Deployment
       items:
       - name: ARM template