fn split_namespace(class: &str) -> (StdOption<&str>, &str) {
    let idx = class.rfind('\\');

    if let Some(idx) = idx {
        (Some(&class[0..idx]), &class[idx + 1..])
    } else {
        (None, class)
    }
}
Takes a class name and splits the namespace off from the actual class name.

# Returns

A tuple, where the first item is the namespace (or [`None`] if not
namespaced), and the second item is the class name.
src/describe/stub.rs