Extraneous comas in modified example

Created by: GuillaumeLeclerc

Hello,

I just modified a simple example and i have an invalid result:

syntax m = ctx => {
  let delim = ctx.next().value;
  var arr = [];
  for (let item of delim.inner()) {
    arr.push(item);
    arr.push(item);
  }
  return #`[${arr}]`;
}

m {
  1, 2, 3, "sdf"
}

output:

[1, 1, , 2, 2, , 3, 3, , "sdf", "sdf"]