message: Fix crate import for proc_macro
diff: @@ -16,7 +16,7 @@ use std::iter;
  use std::mem;
  use std::str::FromStr;
  -use proc_macro::TokenStream;
  +use crate::proc_macro::TokenStream;
  use syn::{Body, VariantData, Ident, Ty, ConstExpr, Attribute, TyGenerics};
  #[proc_macro_derive(H5Type)]
  