one-liners for the remaining top-50 dart:core classes

sdk/lib/core/set.dart

 // Copyright (c) 2011, 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.
 
 part of dart.core;
 
 /**
- * A `Set` is a collection of elements where each element can occur only once.
+ * A collection of objects in which each object can occur only once.
  *
  * That is, for each object of the element type, the object is either considered
- * to be in the set, or it is not in the set.
+ * to be in the set, or to _not_ be in the set. 

[Lasse Reichstein Nielsen, 2016/08/31 18:57:37]

Trailing space, please remove.

  *
  * Set implementations may consider some elements indistinguishable. These
- * objects will be treated as being the same for any operation on the set.
+ * elements are treated as being the same for any operation on the set.
  *
  * The default `Set` implementation, [HashSet], considers objects
  * indistinguishable if they are equal with regard to [Object.operator==].
  *
  * Sets may be either ordered or unordered. [HashSet] is unordered and doesn't
  * guarantee anything about the order that elements are accessed in by
  * iteration. [LinkedHashSet] iterates in the insertion order of its elements.
  */
 abstract class Set<E> extends IterableBase<E> {
   /**
@@ skipping 88 matching lines @@
    * That is, the returned set contains all the elements of this `Set` that
    * are not elements of [other].
    */
   Set<E> difference(Set<E> other);
 
   /**
    * Removes all elements in the set.
    */
   void clear();
 }