I am not entirely sure about the extra spaces, but I'm not sure if there is a better way of dealing with this either

For this specific Assist, you could right-extend the delete span into SPACE (not COMMENT) by checking node.last_token()?.next_token(). Note that it cannot be left-extend, considering let inherit;in 1.

{
  a = 1;
  /*inherit;
  */b = 2;
}

=>

{
  a = 1;
  b = 2;
}

let /*inherit; */in 1

=>

let in 1