Nested imports with use

A new way to write use statements has been added to Rust: nested import groups. If you’ve ever written a set of imports like this:

#![allow(unused)]
fn main() {
use std::fs::File;
use std::io::Read;
use std::path::{Path, PathBuf};
}

You can now write this:

#![allow(unused)]
fn main() {
mod foo {
// on one line
use std::{fs::File, io::Read, path::{Path, PathBuf}};
}

mod bar {
// with some more breathing room
use std::{
    fs::File,
    io::Read,
    path::{
        Path,
        PathBuf
    }
};
}
}

This can reduce some repetition, and make things a bit more clear.