fix test expectation doc typo

Change-Id: I57aeac20269a2527e81822a550d483ab34064c6c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/385081
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Phil Quitslund <pquitslund@google.com>
Auto-Submit: Phil Quitslund <pquitslund@google.com>
diff --git a/pkg/analysis_server/test/src/computer/outline_computer_test.dart b/pkg/analysis_server/test/src/computer/outline_computer_test.dart
index 75645a4..e398405 100644
--- a/pkg/analysis_server/test/src/computer/outline_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/outline_computer_test.dart
@@ -405,7 +405,7 @@
 part 'test.dart';
 
 class C {
-  // Endure that the outline for the augment doesn't include members from the
+  // Ensure that the outline for the augment doesn't include members from the
   // augmented class.
   void n() {}
 }