export async function not correctly minified

[limsbeheer]

Describe the bug When exporting an async function the minified code is incorrect (using version 1.20.6)

To Reproduce See dotnetfiddle:

using System;
using static NUglify.Uglify;

public class Program
{
  public static void Main()
  {
    Console.WriteLine(Js("export async function fooAsync(){}"));
  }
}

Minified output export{async}

Expected output code export async function fooAsync(){}

[limsbeheer]

Thank you!