Returns the rejection value from the closest Await.
import { Await, useAsyncError } from "react-router";
function ErrorElement() {
  const error = useAsyncError();
  return (
    <p>Uh Oh, something went wrong! {error.message}</p>
  );
}
// somewhere in your app
<Await
  resolve={promiseThatRejects}
  errorElement={<ErrorElement />}
/>;
useAsyncError(): unknown