message: Use const_frozen_string! in generated code
  Summary: Less code.
diff: @@ -30,12 +30,7 @@ impl StarFun {
  match &self.type_attribute {
  Some(x) => quote_spanned! {
  self.span()=>
  - std::option::Option::Some({
  - const TYPE_N: usize = #x.len();
  - static TYPE: starlark::values::StarlarkStrNRepr<TYPE_N> =
  - starlark::values::StarlarkStrNRepr::new(#x);
  - TYPE.unpack()
  - })
  + std::option::Option::Some(starlark::const_frozen_string!(#x).to_frozen_value())
  },
  None => {
  quote_spanned! {
  