Added API description for Message::get_status

include/cppkafka/message.h

@@ -188,6 +188,9 @@ public:
 #endif
 
 #if (RD_KAFKA_VERSION >= RD_KAFKA_MESSAGE_STATUS_SUPPORT_VERSION)
+    /**
+     * \brief Gets the message persistence status
+     */
     rd_kafka_msg_status_t get_status() const {
         assert(handle_);
         return rd_kafka_message_status(handle_.get());