Clarify support for SAS token authentication

Author: gholliday

articles/event-hubs/apache-kafka-frequently-asked-questions.yml

@@ -38,6 +38,13 @@ sections:
           - They fully distinct from Event Hubs consumer groups. You **don't** need to use '$Default', nor do you need to worry about Kafka clients interfering with AMQP workloads.
           - They aren't viewable in the Azure portal. Consumer group info is accessible via Kafka APIs.
           
+      - question: |
+          Does Azure Event Hubs for Apache Kafka support shared access signature token authentication?
+        answer: |
+          Authenticating using [OAuth 2.0 and Shared access signature](event-hubs-for-kafka-ecosystem-overview#security-and-authentication) is supported.
+          
+          Shared access signature tokens are [generated](authenticate-shared-access-signature.md#generate-a-shared-access-signature-token) using an authorization rule and one of its signing keys. This is not supported when using the Event Hubs for Apache Kafka endpoint.
+
 additionalContent: |
 
   ## Next steps