warn unused_doc_comments for macros

Question

How can I add and use doc comments with a macro invocation?

macro_rules! foo {
(
    $(#[$outer:meta])*
    $name:ident
) => {
        pub mod $name {
            $(#[$outer])*
            pub const THE_ANSWER: i32 = 42;
        }
    }
}

/// doc for macro created module
foo!(bar);

fn main() {
    println!("{}", bar::THE_ANSWER);
}

Playground Link

I seem to be doing what's recommended by this question but I still get the warning.

warning: unused doc comment
   --> src/main.rs:13:1
   |
13 | /// doc for macro created module
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ rustdoc does not generate documentation for macro invocations
   |
   = note: `#[warn(unused_doc_comments)]` on by default
   = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion