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/testing/crash_test.rs b/library/alloc/src/testing/crash_test.rs
index ff72f99b2cb..684bac60d9a 100644
--- a/library/alloc/src/testing/crash_test.rs
+++ b/library/alloc/src/testing/crash_test.rs
@@ -1,6 +1,8 @@
-use crate::fmt::Debug; // the `Debug` trait is the only thing we use from `crate::fmt`
 use std::cmp::Ordering;
-use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
+use std::sync::atomic::AtomicUsize;
+use std::sync::atomic::Ordering::SeqCst;
+
+use crate::fmt::Debug; // the `Debug` trait is the only thing we use from `crate::fmt`
 
 /// A blueprint for crash test dummy instances that monitor particular events.
 /// Some instances may be configured to panic at some point.