minor: remove whitespaces in remove use-tree braces

[A4-Tacks]

Example

struct X; struct Y;
mod z {
    $0use super::{
        X, Y,
    };$0
    fn w() { let x = X; }
}

Before this PR

struct X; struct Y;
mod z {
    use super::
        X
    ;
    fn w() { let x = X; }
}

After this PR

struct X; struct Y;
mod z {
    use super::X;
    fn w() { let x = X(); }
}