GH-2934: Non-Blocking Retries and transactions

Fixes: #2934

* Non-Blocking Retries cannot be combined with container transactions

* Update docs in `transactions.adoc` and `retrytopic.adoc`

(cherry picked from commit 3449f8c)

spring-kafka-docs/src/main/antora/modules/ROOT/pages/kafka/transactions.adoc

@@ -79,6 +79,9 @@ Instead, use a `KafkaTransactionManager` in the container to start the Kafka tra
 
 See xref:tips.adoc#ex-jdbc-sync[Examples of Kafka Transactions with Other Transaction Managers] for an example application that chains JDBC and Kafka transactions.
 
+IMPORTANT: xref:retrytopic.adoc[Non-Blocking Retries] cannot combine with xref:kafka/transactions.adoc#container-transaction-manager[Container Transactions].
+When the listener code throws an exception, container transaction commit succeeds, and the record is sent to the retryable topic.
+
 [[kafkatemplate-local-transactions]]
 == `KafkaTemplate` Local Transactions
 

spring-kafka-docs/src/main/antora/modules/ROOT/pages/retrytopic.adoc

@@ -9,3 +9,4 @@ Since 2.7 Spring for Apache Kafka offers support for that via the `@RetryableTop
 
 IMPORTANT: Non-blocking retries are not supported with xref:kafka/receiving-messages/listener-annotation.adoc#batch-listeners[Batch Listeners].
 
+IMPORTANT: Non-Blocking Retries cannot combine with xref:kafka/transactions.adoc#container-transaction-manager[Container Transactions].