Fix documentation for LinkedHashSet.

sdk/lib/collection/linked_hash_set.dart

Index: sdk/lib/collection/linked_hash_set.dart
diff --git a/sdk/lib/collection/linked_hash_set.dart b/sdk/lib/collection/linked_hash_set.dart
index 2053251c16704c3e86e6c45d1b86910f5f34784c..5addba5b092da40423585967a4167465f153e900 100644
--- a/sdk/lib/collection/linked_hash_set.dart
+++ b/sdk/lib/collection/linked_hash_set.dart
@@ -92,7 +92,7 @@ abstract class LinkedHashSet<E> implements HashSet<E> {
    * Create a linked hash set containing all [elements].
    *
    * Creates a linked hash set as by `new LinkedHashSet<E>()` and adds each
-   * element of`elements` to this set in the order they are iterated.
+   * element of `elements` to this set in the order they are iterated.
    *
    * All the [elements] should be assignable to [E].
    * The `elements` iterable itself may have any element type,