src/language-js/print/jsx.js/printJsxSpreadAttribute
function printJsxSpreadAttribute(path, options, print) {
  const n = path.getValue();
  return concat([
    "{",
    path.call(
      (p) => {
        const printed = concat(["...", print(p)]);
        const n = p.getValue();
        if (!hasComment(n) || !willPrintOwnComments(p)) {
          return printed;
        }
        return concat([
          indent(concat([softline, printComments(p, () => printed, options)])),
          softline,
        ]);
      },
      n.type === "JSXSpreadAttribute" ? "argument" : "expression"
    ),
    "}",
  ]);
}