[AzureAD-Passwordless] Add graphic, TOC entry

Author: iainfoulds

articles/active-directory/authentication/TOC.yml

@@ -138,7 +138,11 @@
       - name: Passwordless security keys
         href: howto-authentication-passwordless-security-key.md
       - name: Passwordless Windows 10
-        href: howto-authentication-passwordless-security-key-windows.md
+        items:
+          - name: Azure AD joined devices
+            href: howto-authentication-passwordless-security-key-windows.md
+          - name: Hybrid Azure AD joined devices
+            href: howto-authentication-passwordless-security-key-on-premises.md
       - name: Passwordless phone sign-in
         href: howto-authentication-passwordless-phone.md
       - name: Windows Hello for Business