Named parameters not set in query v2.2.0

When running the following example code in the documents

```

query := "SELECT x.* FROM `travel-sample` x WHERE x.`type`=$type LIMIT 10;"

params := make(map[string]interface{}, 1)

params["type"] = "hotel"

rows, err := cluster.Query(query, &gocb.QueryOptions{NamedParameters: params})

```

The `$type` parameter is not set in the query upon execution.