`#[derive(H5Type)]` always produces a compiler warning.

[ethyssen]

use hdf5::H5Type;

#[derive(H5Type)]
#[repr(C)]
pub struct Byte(u8);

^^ This code produces a compiler warning:

warning: non-local `impl` definition, `impl` blocks should be written at the same level as their item
 --> src/main.rs:3:10
  |
3 | #[derive(H5Type)]
  |          ^-----
  |          |
  |          `H5Type` is not local
  |          move the `impl` block outside of this constant `_IMPL_H5TYPE_FOR_Byte`
4 | #[repr(C)]
5 | pub struct Byte(u8);
  |            ---- `Byte` is not local