Bridge attribute breaks inner attributes

[dtolnay]

#[cxx::bridge]
mod ffi {
    #![deny(missing_docs)]

    unsafe extern "C++" {
        include!("example/include/header.h");

        /// wow
        fn f();
    }
}

pub use self::ffi::*;

error: an inner attribute is not permitted in this context
 --> src/main.rs:3:5
  |
3 |     #![deny(missing_docs)]
  |     ^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: inner attributes, like `#![no_std]`, annotate the item enclosing them, and are usually found at the beginning of source files. Outer attributes, like `#[test]`, annotate the item following them.

Probably what's going wrong is we are accidentally transporting the inner attributes out to outside of the corresponding item in the macro output, which is not where they are supposed to go.