Issue 26821. Don't add 'void' return type for setters when lint 'avoid_return_types_on_setters' is …

pkg/analysis_server/test/services/correction/fix_test.dart

 // Copyright (c) 2014, 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.
 
 library test.services.correction.fix;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/plugin/edit/fix/fix_dart.dart';
@@ skipping 2613 matching lines @@
   set s1(x) {
     // TODO: implement s1
   }
 
   @override
   set s2(int x) {
     // TODO: implement s2
   }
 
   @override
-  void set s3(String x) {
+  set s3(String x) {
     // TODO: implement s3
   }
 }
 ''');
   }
 
   test_createNoSuchMethod() async {
     resolveTestUnit('''
 abstract class A {
   m1();
@@ skipping 2684 matching lines @@
   @override
   void t() { }
 }
 ''');
   }
 
   void verifyResult(String expectedResult) {
     expect(resultCode, expectedResult);
   }
 }