Update toc.yml

Author: bashan-git

articles/communication-services/toc.yml

@@ -388,6 +388,16 @@ items:
       href: https://azure.github.io/azure-sdk-for-java/communication.html#azure-communication-sms
     - name: SMS (Python)
       href: https://azure.github.io/azure-sdk-for-python/communication.html#azure-communication-sms
+   - name: Email libraries
+    items:
+    - name: Email (JavaScript)
+      href: https://azure.github.io/azure-sdk-for-js/communication.html#azure-communication-email
+    - name: Email (.NET)
+      href: https://azure.github.io/azure-sdk-for-net/communication.html#azure-communication-email
+    - name: Email (Java)
+      href: https://azure.github.io/azure-sdk-for-java/communication.html#azure-communication-email
+    - name: Email (Python)
+      href: https://azure.github.io/azure-sdk-for-python/communication.html#azure-communication-email
   - name: Identity libraries
     items:
     - name: Identity (JavaScript)