rustfmt prints "rewriting static" in its output

[asomers]

Commit 30cdc2b from #6204 included what looks like a debugging println! that causes rustfmt to generate invalid rust code. I don't have a minimal test case, but it's causing failures in combination with bindgen in at least 3 other crates.
Downstream bug: rust-lang/rust#126887

[compiler-errors]

I've put up a fix in-tree in rust-lang/rust rust-lang/rust#126888 which can later get subtree-sync'd here. @calebcartwright @ytmimi i'm happy to perform the rust->rustfmt subtree sync to pull this in if you'd like.

[calebcartwright]

Definitely agreed with getting the fix in directly. If you're up for doing a subtree push to bring that over here then that's helpful as well (though not urgent nor impactful on this side)

[compiler-errors]

Cool, I can do a push tomorrow when this lands.

[rami3l]

@calebcartwright Maybe adding some disallowed rules (https://rust-lang.github.io/rust-clippy/master/#/disallowed) will prevent this from happening again?