message: Mark StringIterGen as not serializable
diff: @@ -24,7 +24,7 @@ use crate as starlark;
  use crate::values::{Heap, StarlarkValue, Value, ValueLike};
  /// An opaque iterator over a string, produced by elems/codepoints
  -#[derive(Debug, Trace, Coerce, Display, Freeze)]
  +#[derive(Debug, Trace, Coerce, Display, Freeze, NoSerialize)]
  #[display(fmt = "iterator")]
  #[repr(C)]
  struct StringIteratorGen<V> {
  