Update toc.yml

Author: evachen96

articles/healthcare-apis/fhir/toc.yml

@@ -36,7 +36,7 @@ items:
       expanded: true
       items: 
         - name: Use Azure AD B2C for an identity provider
-          href: azure-ad-b2c-overview.md
+          href: azure-ad-b2c-setup.md
         - name: Configure multiple service identity providers
           href: configure-identity-providers.md
         - name: Troubleshoot identity provider configuration