Update toc.yml

Author: msmbaldwin

articles/key-vault/general/toc.yml

@@ -6,12 +6,14 @@
     href: overview.md
   - name: About keys, secrets, and certificates
     href: about-keys-secrets-certificates.md
-- name: Keys documentation
-  href: ../keys/about-keys.md
-- name: Secrets documentation
-  href: ../secrets/about-secrets.md
-- name: Certificates documentation
-  href: ../certificates/about-certificates.md
+- name: Docs for keys, secrets, and certificates
+  items:
+  - name: Keys
+    href: ../keys/about-keys.md
+  - name: Secrets
+    href: ../secrets/about-secrets.md
+  - name: Certificates
+    href: ../certificates/about-certificates.md
 - name: Quickstarts
   expanded: true
   items:
@@ -225,4 +227,3 @@
     href: /archive/blogs/kv/
   - name: Product Feedback
     href: https://feedback.azure.com/d365community/forum/285c5ae0-f524-ec11-b6e6-000d3a4f0da0
-