pub fn new(diff: &'b SummaryDiff<'a>) -> Self {
        let sorted_target = Self::make_sorted(&diff.target_packages);
        let sorted_host = Self::make_sorted(&diff.host_packages);

        Self {
            diff,
            sorted_target,
            sorted_host,
        }
    }
Creates a new `SummaryReport` that can be displayed.
guppy-summaries/src/report.rs