Function format_line_log_diff 

pub fn format_line_log_diff(
    prefix: &str,
    old_path: &str,
    new_path: &str,
    old_data: &[u8],
    new_data: &[u8],
    ranges: &RangeSet,
    touched: &DiffRanges,
) -> String

Format hacky line-log hunk (Git dump_diff_hacky_one).