Update how-to storage structure TOC

Author: MGoedtel

articles/aks/TOC.yml

@@ -374,14 +374,14 @@
           href: azure-netapp-files.md
         - name: Use Azure Ultra Disks
           href: use-ultra-disks.md
-        - name: CSI Storage Drivers
-          items:
-            - name: Enable CSI Storage Drivers
-              href: csi-storage-drivers.md
-            - name: Azure Disk CSI drivers
-              href: azure-disk-csi.md
-            - name: Azure Files CSI drivers
-              href: azure-files-csi.md
+    - name: CSI Storage Drivers
+      items:
+        - name: Enable CSI Storage Drivers
+          href: csi-storage-drivers.md
+        - name: Azure Disk CSI drivers
+          href: azure-disk-csi.md
+        - name: Azure Files CSI drivers
+          href: azure-files-csi.md
     - name: Monitoring and logging
       items:
         - name: Monitor AKS