update preview ToC to align with new reference-unified.yml

Author: scbedd

docs-ref-mapping/reference-preview.yml

@@ -12,7 +12,7 @@
         href: ~/docs-ref-services/preview/mgmt-advisor-readme.md
         children:
         - azure-mgmt-advisor
-  - name: Agrifood
+  - name: AgriFood
     href: ~/docs-ref-services/preview/agrifood.md
     landingPageType: Service
     items:
@@ -22,6 +22,18 @@
         href: ~/docs-ref-services/preview/mgmt-agrifood-readme.md
         children:
         - azure-mgmt-agrifood
+  - name: AI
+    href: ~/docs-ref-services/preview/ai.md
+    landingPageType: Service
+    items:
+    - name: AI Generative
+      href: ~/docs-ref-services/preview/ai-generative-readme.md
+      children:
+      - azure-ai-generative
+    - name: AI Resources
+      href: ~/docs-ref-services/preview/ai-resources-readme.md
+      children:
+      - azure-ai-resources
   - name: AKS Developer Hub
     href: ~/docs-ref-services/preview/aks-developer-hub.md
     landingPageType: Service