forgot use stmt

Author: William Utter

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -4,7 +4,7 @@ use crate::query::Providers;
 use crate::traits::util::supertraits_for_pretty_printing;
 use crate::ty::GenericArgKind;
 use crate::ty::{
-    ConstInt, ParamConst, ScalarInt, Term, TermKind, TypeFoldable, TypeSuperFoldable,
+    ConstInt, Expr, ParamConst, ScalarInt, Term, TermKind, TypeFoldable, TypeSuperFoldable,
     TypeSuperVisitable, TypeVisitable, TypeVisitableExt,
 };
 use rustc_apfloat::ieee::{Double, Single};