aws sqs --wait-time-seconds documentation is incorrect

In the help page for the `aws sqs receive-message` command, it says:

```
--wait-time-seconds (integer)
The duration (in seconds) for which the call waits for a message to
arrive in the queue before returning. If a message is available, the
call returns sooner than WaitTimeSeconds . If no messages are avail-
able and the wait time expires, the call returns successfully with
an empty list of messages.
```

It mentions that if there are no messages, an empty list is returned. However, the behavior I've seen is that the command will not return an empty list, but rather nothing at all.

```sh
➜ ~ aws sqs receive-message --visibility-timeout 0 --max-number-of-messages 10 --wait-time-seconds 5 --queue-url 'https://us-west-2.queue.amazonaws.com/123456789123/somequeue'
➜ ~
```