Remove box syntax for Box<ImplItem> construction

ImplItem only has 80 bytes according to compiler internal rustdoc.

Author: est31

src/librustdoc/clean/auto_trait.rs

@@ -117,15 +117,15 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
             attrs: Default::default(),
             visibility: Inherited,
             item_id: ItemId::Auto { trait_: trait_def_id, for_: item_def_id },
-            kind: box ImplItem(Impl {
+            kind: Box::new(ImplItem(Impl {
                 unsafety: hir::Unsafety::Normal,
                 generics: new_generics,
                 trait_: Some(trait_ref.clean(self.cx)),
                 for_: ty.clean(self.cx),
                 items: Vec::new(),
                 polarity,
                 kind: ImplKind::Auto,
-            }),
+            })),
             cfg: None,
         })
     }

src/librustdoc/clean/blanket_impl.rs

@@ -106,7 +106,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                         attrs: Default::default(),
                         visibility: Inherited,
                         item_id: ItemId::Blanket { impl_id: impl_def_id, for_: item_def_id },
-                        kind: box ImplItem(Impl {
+                        kind: Box::new(ImplItem(Impl {
                             unsafety: hir::Unsafety::Normal,
                             generics: clean_ty_generics(
                                 cx,
@@ -123,8 +123,8 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                                 .map(|x| x.clean(cx))
                                 .collect::<Vec<_>>(),
                             polarity: ty::ImplPolarity::Positive,
-                            kind: ImplKind::Blanket(box trait_ref.0.self_ty().clean(cx)),
-                        }),
+                            kind: ImplKind::Blanket(Box::new(trait_ref.0.self_ty().clean(cx))),
+                        })),
                         cfg: None,
                     });
                 }