Tighten the span around index operators.

lib/src/chunk.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 dart_style.src.chunk;
 
 import 'fast_hash.dart';
 import 'nesting_level.dart';
 import 'rule/rule.dart';
 
@@ skipping 311 matching lines @@
 
   /// Splitting the internals of collection literal arguments.
   ///
   /// Used to prefer splitting at the argument boundary over splitting the
   /// collection contents.
   static const splitCollections = 2;
 
   /// Splitting on the "." in a named constructor.
   static const constructorName = 3;
 
+  /// Splitting a `[...]` index operator.
+  static const index = 3;
+
   /// Splitting before a type argument or type parameter.
   static const typeArgument = 4;
 }
 
 /// The in-progress state for a [Span] that has been started but has not yet
 /// been completed.
 class OpenSpan {
   /// Index of the first chunk contained in this span.
   int get start => _start;
   int _start;
@@ skipping 47 matching lines @@
   /// output. This way, commented out chunks of code do not get erroneously
   /// re-indented.
   final bool flushLeft;
 
   /// Whether this comment is an inline block comment.
   bool get isInline => linesBefore == 0 && !isLineComment;
 
   SourceComment(this.text, this.linesBefore,
       {this.isLineComment, this.flushLeft});
 }