A macro to evaluate, as a boolean, whether an expression matches a pattern.

For users who build using only Rust 1.42 and newer, consider using [`std::matches`], which
is included in the [standard library prelude] and thus is automatically in scope.

[`std::matches`]: core::matches
[standard library prelude]: https://doc.rust-lang.org/stable/reference/names/preludes.html
