Reformat use declarations.

The previous commit updated `rustfmt.toml` appropriately. This commit is
the outcome of running `x fmt --all` with the new formatting options.

Author: nnethercote

alloc/src/collections/btree/set/tests.rs

@@ -1,8 +1,9 @@
+use std::ops::Bound::{Excluded, Included};
+use std::panic::{catch_unwind, AssertUnwindSafe};
+
 use super::*;
 use crate::testing::crash_test::{CrashTestDummy, Panic};
 use crate::testing::rng::DeterministicRng;
-use std::ops::Bound::{Excluded, Included};
-use std::panic::{catch_unwind, AssertUnwindSafe};
 
 #[test]
 fn test_clone_eq() {

alloc/src/collections/btree/split.rs

@@ -1,8 +1,10 @@
-use super::node::{ForceResult::*, Root};
-use super::search::SearchResult::*;
 use core::alloc::Allocator;
 use core::borrow::Borrow;
 
+use super::node::ForceResult::*;
+use super::node::Root;
+use super::search::SearchResult::*;
+
 impl<K, V> Root<K, V> {
     /// Calculates the length of both trees that result from splitting up
     /// a given number of distinct key-value pairs.