Don't include parameter names in types, don't use Unicode arrow.

pkg/front_end/testcases/inference/block_bodied_lambdas_async_star.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /*@testedFeatures=inference*/
 library test;
 
 import 'dart:async';
 
 main() {
-  var /*@type=() → Stream<num>*/ f = /*@returnType=Stream<num>*/ () async* {
+  var /*@type=() -> Stream<num>*/ f = /*@returnType=Stream<num>*/ () async* {
     yield 1;
     Stream<double> s;
     yield* /*@promotedType=none*/ s;
   };
   Stream<num> g = /*@promotedType=none*/ f();
   Stream<int> h = /*info:ASSIGNMENT_CAST*/ /*@promotedType=none*/ f();
 }