Function build

libs/error-stack/tests/test_iter.rs:47–66

Builds the following tree: ```text A G / \ | B E H / \ | C D F ``` which will result in this report: ```text A ╰┬▶ B │ ╰┬▶ C │ ╰▶ D ╰▶ E ╰─▶ F G ╰─▶ H ```

()

/// ╰─▶ H
/// ```
fn build() -> Report<[Char]> {
    let mut report_c = Char('C').into_report().expand();
    let report_d = Char('D').into_report();

    report_c.push(report_d);
    let mut report_b = report_c.change_context(Char('B')).expand();

    let report_f = Char('F').into_report();
    let report_e = report_f.change_context(Char('E'));

    report_b.push(report_e);

    let mut report_a = report_b.change_context(Char('A')).expand();

    let report_h = Char('H').into_report();
    let report_g = report_h.change_context(Char('G'));

    report_a.push(report_g);
    report_a
}

/// Try to verify if the topological sorting is working, by trying to verify that:
///