Fix some bad documentation links.

sdk/lib/core/object.dart

Index: sdk/lib/core/object.dart
diff --git a/sdk/lib/core/object.dart b/sdk/lib/core/object.dart
index 34a008461ed21f2a531d737db03ac664e9469607..fda5662d14cbba92e2f4cd2ae3a417be1d69cbc9 100644
--- a/sdk/lib/core/object.dart
+++ b/sdk/lib/core/object.dart
@@ -49,7 +49,7 @@ class Object {
    *  * Transitive: For all objects `o1`, `o2`, and `o3`, if `o1 == o2` and
    *    `o2 == o3` are true, then `o1 == o3` must be true.
    *
-   * The method should also be consistent over time, 
+   * The method should also be consistent over time,
    * so whether two objects are equal should only change
    * if at least one of the objects was modified.
    *
@@ -63,15 +63,15 @@ class Object {
    *
    * A hash code is a single integer which represents the state of the object
    * that affects [==] comparisons.
-   * 
-   * All objects have hash codes. 
-   * The default hash code represents only the identity of the object, 
+   *
+   * All objects have hash codes.
+   * The default hash code represents only the identity of the object,
    * the same way as the default [==] implementation only considers objects
    * equal if they are identical (see [identityHashCode]).
-   * 
-   * If [==] is overridden to use the object state instead, 
-   * the hash code must also be changed to represent that state. 
-   * 
+   *
+   * If [==] is overridden to use the object state instead,
+   * the hash code must also be changed to represent that state.
+   *
    * Hash codes must be the same for objects that are equal to each other
    * according to [==].
    * The hash code of an object should only change if the object changes
@@ -79,12 +79,12 @@ class Object {
    * There are no further requirements for the hash codes.
    * They need not be consistent between executions of the same program
    * and there are no distribution guarantees.
-   * 
+   *
    * Objects that are not equal are allowed to have the same hash code,
    * it is even technically allowed that all instances have the same hash code,
    * but if clashes happen too often, it may reduce the efficiency of hash-based
    * data structures like [HashSet] or [HashMap].
-   * 
+   *
    * If a subclass overrides [hashCode], it should override the
    * [==] operator as well to maintain consistency.
    */