Fix JavaDocs errors

Related to #2239

**Cherry-pick to `2.9.x`**

Author: artembilan

Diff for: spring-kafka/src/main/java/org/springframework/kafka/listener/ContainerPartitionPausingBackOffManagerFactory.java

@@ -19,7 +19,7 @@
 import org.springframework.util.Assert;
 
 /**
- * A factory for {@link ContainerPartitionPausingBackoffManager}.
+ * A factory for {@link ContainerPartitionPausingBackOffManager}.
  *
  * @author Gary Russell
  * @since 2.9

Diff for: spring-kafka/src/main/java/org/springframework/kafka/retrytopic/RetryTopicConfigurationSupport.java

@@ -265,7 +265,6 @@ protected Consumer<DestinationTopicResolver> configureDestinationTopicResolver()
 	/**
 	 * Create the {@link KafkaConsumerBackoffManager} instance that will be used to
 	 * back off partitions.
-	 * To configure it, override the {@link #configureKafkaBackOffManager} method.
 	 * To provide a custom implementation, either override this method, or
 	 * override the {@link RetryTopicComponentFactory#kafkaBackOffManagerFactory} method
 	 * and return a different {@link KafkaBackOffManagerFactory}.