Rustfmt Macro with $( tt )* can introduce breaking comma

[JulianKnodt]

Without running rustfmt, this macro compiles (albeit it does look very strange).
After running rustfmt, it introduces a comma between functions which leads to it no longer compiling.

https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=0d69aa8f44c299d2726f3e39e6c535ff

Inlined:

macro_rules! document {
  ($t: ty, $( $code_block: tt )*)=> {
    const DOC: &'static str = stringify!($( $code_block )*);

    $( $code_block )*
  }
}
struct T;

document!(T, fn example() {} fn other() {});
// ^ Comma is introduced here: `fn example() {}, fn other() {}`

fn main() {}

[ytmimi]

Thanks for reaching out. I believe this is a duplicate of #4375 and #4631