term: Don't run the code example, just compile it

This is blocking a snapshot because apparently the test fails on the bots.

src/libterm/lib.rs

@@ -18,7 +18,7 @@
 //!
 //! ## Example
 //!
-//! ```rust
+//! ```no_run
 //! extern crate term;
 //!
 //! fn main() {