Clarify doc for Duration equals

Fixes #35273

Previous wording made it seem like the behavior was the same as
`identical`.

Change-Id: Ib7fdb183a26a4e2b3c849dd72cb515aa1652028d
Reviewed-on: https://dart-review.googlesource.com/c/85465
Reviewed-by: Kevin Moore <kevmoo@google.com>
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>
Commit-Queue: Lasse R.H. Nielsen <lrn@google.com>
diff --git a/sdk/lib/core/duration.dart b/sdk/lib/core/duration.dart
index 7e192c2..52bfc29 100644
--- a/sdk/lib/core/duration.dart
+++ b/sdk/lib/core/duration.dart
@@ -211,7 +211,7 @@
   int get inMicroseconds => _duration;
 
   /**
-   * Returns `true` if this [Duration] is the same object as [other].
+   * Returns `true` if this [Duration] has the same value as [other].
    */
   bool operator ==(dynamic other) =>
       other is Duration && _duration == other.inMicroseconds;