Rollup merge of #126717 - nnethercote:rustfmt-use-pre-cleanups, r=jieyouxu

Clean up some comments near `use` declarations

#125443 will reformat all `use` declarations in the repository. There are a few edge cases involving comments on `use` declarations that require care. This PR cleans up some clumsy comment cases, taking us a step closer to #125443 being able to merge.

r? ``@lqd``

compiler/rustc_trait_selection/src/traits/normalize.rs

@@ -1,4 +1,5 @@
 //! Deeply normalize types using the old trait solver.
+
 use super::error_reporting::OverflowCause;
 use super::error_reporting::TypeErrCtxtExt;
 use super::SelectionContext;

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -6,6 +6,7 @@
 //!
 //! [rustc dev guide]:
 //! https://rustc-dev-guide.rust-lang.org/traits/resolution.html#confirmation
+
 use rustc_ast::Mutability;
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_hir::lang_items::LangItem;