Invalid mqtt.md pause documentation

When sending:

```json
{
    "print": {
        "sequence_id": "0",
        "command": "pause",
        "param": ""
    }
}
```

The response is almost always:

```json
{
  "print": {
    "command": "pause",
    "sequence_id": "2868",
    "param": "",
    "err_code": 84033543
  }
}
```
