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_middle/src/middle/privacy.rs

@@ -1,6 +1,7 @@
 //! A pass that checks to make sure private fields and methods aren't used
 //! outside their scopes. This pass will also generate a set of exported items
 //! which are available for use externally when compiled as a library.
+
 use crate::ty::{TyCtxt, Visibility};
 use rustc_data_structures::fx::{FxIndexMap, IndexEntry};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};

compiler/rustc_middle/src/mir/statement.rs

@@ -1,4 +1,5 @@
-/// Functionality for statements, operands, places, and things that appear in them.
+//! Functionality for statements, operands, places, and things that appear in them.
+
 use super::{interpret::GlobalAlloc, *};
 
 ///////////////////////////////////////////////////////////////////////////

compiler/rustc_middle/src/mir/terminator.rs

@@ -1,4 +1,5 @@
-/// Functionality for terminators and helper types that appear in terminators.
+//! Functionality for terminators and helper types that appear in terminators.
+
 use rustc_hir::LangItem;
 use smallvec::{smallvec, SmallVec};
 

compiler/rustc_middle/src/ty/abstract_const.rs

@@ -1,4 +1,5 @@
 //! A subset of a mir body used for const evaluability checking.
+
 use crate::ty::{
     self, Const, EarlyBinder, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
     TypeVisitableExt,