Function difft::display::context::before_with_opposites

fn before_with_opposites(
    before_lines: &[LineNumber],
    opposite_lines: &HashMap<LineNumber, HashSet<LineNumber>, BuildHasherDefault<FxHasher>>
) -> Vec<(Option<LineNumber>, Option<LineNumber>)>

Before:

118    --
119    --
120    -- (novel)

After:

118    88 (expanded from closest)
119    89 (closest match)
120    -- (novel)