rustfmt should reorder precise capturing

[oriongonza]

fn a() -> impl Sized + use<> {}
fn b() -> impl use<> + Sized {}

An order should be chosen. Does the use go at the front or at the back?

[ytmimi]

We could try adding a new unstable option for this. Maybe named something like precise _capture_order with three variants Preserve (default), First, and Last.