Method upgrade

repl/src/editor.rs:88–92

Upgrades `self` to at least `new_value`.

(&mut self, new_value: Self)

impl RefreshKind {
    /// Upgrades `self` to at least `new_value`.
    fn upgrade(&mut self, new_value: Self) {
        if new_value > *self {
            *self = new_value;
        }
    }
}

/// An interactive console-based text editor.