Macro __write_docs

macro_rules! __write_docs {
    (
        $(#[child = $child:literal])?
        $(#[inline = $inline:literal])?
        $(#[comment_out = $comment_out:literal])?
        $(#[doc = $doc:expr])*
        $(##[$field_meta:meta])*
        pub $field:ident: $field_ty:ty,

        $document: ident,
    ) => { ... };
}