let mut file_lines = file_content.split('\n');

    let mut file_lines = trim_line_break_suffix(file_content).split('\n');

                    .map(trim_line_break_suffix)

                    let deleted = contents_to_lines(&contents);

                    let deleted =
                        contents_to_lines(trim_line_break_suffix(&contents));

                    let added = contents_to_lines(&contents);

                    let added =
                        contents_to_lines(trim_line_break_suffix(&contents));

                let added = contents_to_lines(&replacement_contents);
                let deleted = contents_to_lines(&change_contents);

                let added = contents_to_lines(trim_line_break_suffix(
                    &replacement_contents,
                ));
                let deleted =
                    contents_to_lines(trim_line_break_suffix(&change_contents));

}
fn trim_line_break_suffix(text: &str) -> &str {
    trim_suffix(text, '\n')
}
// This is a nightly-only experimental API. (trim_prefix_suffix https://github.com/rust-lang/rust/issues/142312)
fn trim_suffix(text: &str, suffix: char) -> &str {
    text.strip_suffix(suffix).unwrap_or(text)