Remove the implied rust; this might make docs.rs actually highlight it properly.
//!
//! model-based testing:
//!
-//! ```rust,no_run
+//! ```no_run
//! #[macro_use]
//! extern crate model;
//! #[macro_use]
//!
//! linearizability testing:
//!
-//! ```rust,no_run
+//! ```no_run
//! #[macro_use]
//! extern crate model;
//! #[macro_use]
