message: Little doc cleanup
diff: //! the connection to work concurrently when possible.
  //!
  //! Pipelining happens automatically when futures are polled concurrently (for example, by using the futures `join`
  -//! combinator). Say we want to prepare 2 statements.
  +//! combinator):
  +//!
  +//! ```rust
  +//! use futures::Future;
  +//! use tokio_postgres::{Client, Error, Statement};
  +//!
  +//! fn pipelined_prepare(client: &mut Client) -> impl Future<Item = (Statement, Statement), Error = Error>
  +//! {
  +//! client.prepare("SELECT * FROM foo")
  +//! .join(client.prepare("INSERT INTO bar (id, name) VALUES ($1, $2)"))
  +//! }
  +//! ```
  //!
  //! # Runtime
  //!
  