Update TLS section in TOC.yml for clarity

Author: christinechen2

articles/storage/blobs/TOC.yml

@@ -379,8 +379,10 @@ items:
           href: ../common/transport-layer-security-configure-minimum-version.md?toc=/azure/storage/blobs/toc.json&bc=/azure/storage/blobs/breadcrumb/toc.json
         - name: Configure TLS version for a client
           href: ../common/transport-layer-security-configure-client-version.md?toc=/azure/storage/blobs/toc.json&bc=/azure/storage/blobs/breadcrumb/toc.json
-        - name: Migrate to TLS 1.2
-          href: ../common/transport-layer-security-configure-migrate-to-TLS2.md?toc=/azure/storage/blobs/toc.json&bc=/azure/storage/blobs/breadcrumb/toc.json
+        - name: TLS version retirement
+          items:
+          - name: Migrate to TLS 1.2
+            href: ../common/transport-layer-security-configure-migrate-to-TLS2.md?toc=/azure/storage/blobs/toc.json&bc=/azure/storage/blobs/breadcrumb/toc.json
       - name: Network routing
         href: ../common/network-routing-preference.md?toc=/azure/storage/blobs/toc.json&bc=/azure/storage/blobs/breadcrumb/toc.json
         items: