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`

2 files changed, 4 insertions, 2 deletions

diff --git a/compiler/rustc_data_structures/src/graph/implementation/mod.rs b/compiler/rustc_data_structures/src/graph/implementation/mod.rs
index 8cf4b4153db..43fdfe6ee0d 100644
--- a/compiler/rustc_data_structures/src/graph/implementation/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/implementation/mod.rs
@@ -20,8 +20,9 @@
 //! the field `next_edge`). Each of those fields is an array that should
 //! be indexed by the direction (see the type `Direction`).
 
-use rustc_index::bit_set::BitSet;
 use std::fmt::Debug;
+
+use rustc_index::bit_set::BitSet;
 use tracing::debug;
 
 #[cfg(test)]
diff --git a/compiler/rustc_data_structures/src/graph/implementation/tests.rs b/compiler/rustc_data_structures/src/graph/implementation/tests.rs
index b4dbd65db94..32a6d9ec881 100644
--- a/compiler/rustc_data_structures/src/graph/implementation/tests.rs
+++ b/compiler/rustc_data_structures/src/graph/implementation/tests.rs
@@ -1,6 +1,7 @@
-use crate::graph::implementation::*;
 use tracing::debug;
 
+use crate::graph::implementation::*;
+
 type TestGraph = Graph<&'static str, &'static str>;
 
 fn create_graph() -> TestGraph {