desactivate doctest on structopt-derive doc
//!
//! First, look at an example:
//!
-//! ```
+//! ```ignore
//! #[derive(StructOpt)]
//! #[structopt(name = "example", about = "An example of StructOpt usage.")]
//! struct Opt {
//!
//! Thus, the `speed` argument is generated as:
//!
-//! ```
+//! ```ignore
//! clap::Arg::with_name("speed")
//! .takes_value(true)
//! .multiple(false)
