src/language-html/utils.js/getLeadingAndTrailingHtmlWhitespace
const getLeadingAndTrailingHtmlWhitespace = (string) => {
  const [, leadingWhitespace, text, trailingWhitespace] = string.match(
    /^([\t\n\f\r ]*)([\S\s]*?)([\t\n\f\r ]*)$/
  );
  return {
    leadingWhitespace,
    trailingWhitespace,
    text,
  };
};