toc for reference and group models

Author: eric-urban

articles/ai-studio/toc.yml

@@ -256,6 +256,8 @@ items:
   - name: Azure AI services REST APIs
     displayName: swagger http
     href: ../ai-services/reference/rest-api-resources.md?context=/azure/ai-studio/context/context
+  - name: Prompt flow Python SDK
+    href: https://microsoft.github.io/promptflow/reference/index.html#
   - name: Azure Policy built-ins
     displayName: samples, policies, definitions
     href: ../ai-services/policy-reference.md?context=/azure/ai-studio/context/context