fn add_changes_to_side<'s>(
side: &mut Side<'s>,
line_num: LineNumber,
src_lines: &[&'s str],
all_matches: &[MatchedPos],
)fn add_changes_to_side<'s>(
side: &mut Side<'s>,
line_num: LineNumber,
src_lines: &[&'s str],
all_matches: &[MatchedPos],
)