src/language-markdown/print-preprocess.js/restoreUnescapedCharacter
function restoreUnescapedCharacter(ast, options) {
  return mapAst(ast, (node) =>
    node.type !== "text" ||
    node.value === "*" ||
    node.value === "_" || // handle these cases in printer
    !isSingleCharRegex.test(node.value) ||
    node.position.end.offset - node.position.start.offset === node.value.length
      ? node
      : {
          ...node,
          value: options.originalText.slice(
            node.position.start.offset,
            node.position.end.offset
          ),
        }
  );
}