message: [ocaml-gen] add 'nonrec' to every type declaration
diff: @@ -284,9 +284,9 @@ pub fn derive_ocaml_enum(item: TokenStream) -> TokenStream {
  let name = <Self as ::ocaml_gen::OCamlDesc>::ocaml_desc(env, &global_generics);
  if new_type {
  - format!("type {} = {}", name, generics_ocaml)
  + format!("type nonrec {} = {}", name, generics_ocaml)
  } else {
  - format!("type {} = {}", rename.expect("type alias must have a name"), name)
  + format!("type nonrec {} = {}", rename.expect("type alias must have a name"), name)
  }
  }
  };
  @@ -558,9 +558,9 @@ pub fn derive_ocaml_gen(item: TokenStream) -> TokenStream {
  let name = <Self as ::ocaml_gen::OCamlDesc>::ocaml_desc(env, &global_generics);
  if new_type {
  - format!("type {} = {}", name, generics_ocaml)
  + format!("type nonrec {} = {}", name, generics_ocaml)
  } else {
  - format!("type {} = {}", rename.expect("type alias must have a name"), name)
  + format!("type nonrec {} = {}", rename.expect("type alias must have a name"), name)
  }
  }
  };
  @@ -685,9 +685,9 @@ pub fn derive_ocaml_custom(item: TokenStream) -> TokenStream {
  let name = <Self as ::ocaml_gen::OCamlDesc>::ocaml_desc(env, &[]);
  if new_type {
  - format!("type {}", name)
  + format!("type nonrec {}", name)
  } else {
  - format!("type {} = {}", rename.expect("type alias must have a name"), name)
  + format!("type nonrec {} = {}", rename.expect("type alias must have a name"), name)
  }
  }
  };
  