Update TOC.yml

Author: jeffpatt24

articles/storage/file-sync/TOC.yml

@@ -187,6 +187,8 @@
     href: /troubleshoot/azure/azure-storage/file-sync-troubleshoot-sync-errors?toc=/azure/storage/file-sync/toc.json
   - name: Troubleshoot cloud tiering issues
     href: /troubleshoot/azure/azure-storage/file-sync-troubleshoot-cloud-tiering?toc=/azure/storage/file-sync/toc.json
+  - name: Troubleshoot managed identities
+    href: /troubleshoot/azure/azure-storage/file-sync-troubleshoot-managed-identities?toc=/azure/storage/file-sync/toc.json
 - name: Reference
   items:
   - name: Azure File Sync agent silent installation