Fix the wrong method return type in documentation

Author: Jiaweizdev

src/reference/asciidoc/amqp.adoc

@@ -1562,9 +1562,9 @@ Object receiveAndConvert() throws AmqpException;
 
 Object receiveAndConvert(String queueName) throws AmqpException;
 
-Message receiveAndConvert(long timeoutMillis) throws AmqpException;
+Object receiveAndConvert(long timeoutMillis) throws AmqpException;
 
-Message receiveAndConvert(String queueName, long timeoutMillis) throws AmqpException;
+Object receiveAndConvert(String queueName, long timeoutMillis) throws AmqpException;
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