Auto merge of #125443 - nnethercote:rustfmt-use-decls, r=lcnr,cuviper,GuillaumeGomez

rustfmt `use` declarations

This PR implements https://github.com/rust-lang/compiler-team/issues/750, which changes how `use` declarations are formatted by adding these options to `rustfmt.toml`:
```
group_imports = "StdExternalCrate"
imports_granularity = "Module"
```

r? `@ghost`

1 files changed, 4 insertions, 2 deletions

diff --git a/library/alloc/src/collections/binary_heap/tests.rs b/library/alloc/src/collections/binary_heap/tests.rs
index d4bc6226a14..1cb07c62149 100644
--- a/library/alloc/src/collections/binary_heap/tests.rs
+++ b/library/alloc/src/collections/binary_heap/tests.rs
@@ -1,7 +1,8 @@
+use std::panic::{catch_unwind, AssertUnwindSafe};
+
 use super::*;
 use crate::boxed::Box;
 use crate::testing::crash_test::{CrashTestDummy, Panic};
-use std::panic::{catch_unwind, AssertUnwindSafe};
 
 #[test]
 fn test_iterator() {
@@ -504,11 +505,12 @@ fn test_retain_catch_unwind() {
 #[cfg(not(target_os = "emscripten"))]
 #[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
 fn panic_safe() {
-    use rand::seq::SliceRandom;
     use std::cmp;
     use std::panic::{self, AssertUnwindSafe};
     use std::sync::atomic::{AtomicUsize, Ordering};
 
+    use rand::seq::SliceRandom;
+
     static DROP_COUNTER: AtomicUsize = AtomicUsize::new(0);
 
     #[derive(Eq, PartialEq, Ord, Clone, Debug)]