Automatically nest use statement paths

[iago-lito]

I read in the book that mod statements like

use a::b;
use a::c;
use a::d::e;
use a::d::f;

Can be reformatted with nested paths like

use a::{
    b, c,
    d::{e, f},
};

What's a consensus about the right way to go?
Is it in the scope of rustfmt to automatically handle this?
If yes, how to configure rustfmt so it does?

[cynecx]

merge_imports (https://github.com/rust-lang/rustfmt/blob/master/Configurations.md).

[iago-lito]

@cynecx Thanks, so merge is the keyword I was missing instead of nest ;)

I read that the default value for this option is false, because the feature is not stabilized yet. See #3362 for discussion about it.