Fix typos in Javadoc

spring-amqp/src/main/java/org/springframework/amqp/support/converter/MessageConversionException.java

@@ -23,7 +23,7 @@
  * Exception to be thrown by message converters if they encounter a problem with converting a message or object.
  * </p>
  * <p>
- * N.B. this is <em>not</em> an {@link AmqpException} because it is a a client exception, not a protocol or broker
+ * N.B. this is <em>not</em> an {@link AmqpException} because it is a client exception, not a protocol or broker
  * problem.
  * </p>
  *

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/annotation/EnableRabbit.java

@@ -104,7 +104,7 @@
  * <p>Annotated methods can use flexible signature; in particular, it is possible to use
  * the {@link org.springframework.messaging.Message Message} abstraction and related annotations,
  * see {@link RabbitListener} Javadoc for more details. For instance, the following would
- * inject the content of the message and a a custom "myCounter" AMQP header:
+ * inject the content of the message and a custom "myCounter" AMQP header:
  *
  * <pre class="code">
  * &#064;RabbitListener(containerFactory = "myRabbitListenerContainerFactory", queues = "myQueue")

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/listener/AbstractRabbitListenerEndpoint.java

@@ -426,7 +426,7 @@ public void setupListenerContainer(MessageListenerContainer listenerContainer) {
 	 * Create a {@link MessageListener} that is able to serve this endpoint for the
 	 * specified container.
 	 * @param container the {@link MessageListenerContainer} to create a {@link MessageListener}.
-	 * @return a a {@link MessageListener} instance.
+	 * @return a {@link MessageListener} instance.
 	 */
 	protected abstract MessageListener createMessageListener(MessageListenerContainer container);