fix: capture mutable reads before later sibling setup runs

[ivov]

Sibling sub-expressions now evaluate left-to-right even when a later sibling needs a lowered setup that mutates state read by an earlier sibling. Previously, the later setup ran first and the earlier read observed the post-mutation value.

fn bump(mut xs: Slice<int>) -> Result<int, error> {
  xs[0] = 2
  Ok(0)
}

fn main() {
  let mut xs = [1]
  fmt.Println(xs[0], bump(xs).is_ok())
}

Previously printed 2 true; now prints 1 true.

[github-actions]

Released in lisette-v0.2.1