src/language-css/printer-postcss.js/isControlDirectiveNode
function isControlDirectiveNode(node) {
  return (
    node.type &&
    node.type === "css-atrule" &&
    node.name &&
    (node.name === "if" ||
      node.name === "else" ||
      node.name === "for" ||
      node.name === "each" ||
      node.name === "while")
  );
}