Fix the obscure corner case of three items in a plural

pkg/intl/lib/intl.dart

 // Copyright (c) 2012, 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.
 
 /**
  * This library provides internationalization and localization. This includes
  * message formatting and replacement, date and number formatting and parsing,
  * and utilities for working with Bidirectional text.
  *
  * This is part of the [intl package]
@@ skipping 251 matching lines @@
     }
     if (other == null) {
       throw new ArgumentError("The 'other' named argument must be provided");
     }
     // TODO(alanknight): This algorithm needs to be locale-dependent.
     switch (howMany) {
       case 0 : return (zero == null) ? other : zero;
       case 1 : return (one == null) ? other : one;
       case 2: return (two == null) ? ((few == null) ? other : few) : two;
       default:
-        if (howMany == 3 || howMany == 4 && few != null) return few;
+        if ((howMany == 3 || howMany == 4) && few != null) return few;
         if (howMany > 10 && howMany < 100 && many != null) return many;
         return other;
     }
     throw new ArgumentError("Invalid plural usage for $howMany");
   }
 
   /**
    * Format a message differently depending on [targetGender]. Normally used as
    * part of an Intl.message message that is to be translated.
    */
@@ skipping 77 matching lines @@
    * unless for some reason this gets called inside a message that resets the
    * locale.
    */
   static String getCurrentLocale() {
     if (defaultLocale == null) defaultLocale = systemLocale;
     return defaultLocale;
   }
 
   toString() => "Intl($locale)";
 }