message: Use batch_execute in example
diff: //! # fn main() -> Result<(), postgres::Error> {
  //! let mut client = Client::connect("host=localhost user=postgres", NoTls)?;
  //!
  -//! client.simple_query("
  +//! client.batch_execute("
  //! CREATE TABLE person (
  //! id SERIAL PRIMARY KEY,
  //! name TEXT NOT NULL,
  