Tweak navigation for 'part of' directives.

pkg/analysis_server/test/analysis/notification_navigation_test.dart

Index: pkg/analysis_server/test/analysis/notification_navigation_test.dart
diff --git a/pkg/analysis_server/test/analysis/notification_navigation_test.dart b/pkg/analysis_server/test/analysis/notification_navigation_test.dart
index f518910ec9193fccf8f3640dee6f587927d9f557..41f3a6ff8d55a2c268fde896017c4a8255819caa 100644
--- a/pkg/analysis_server/test/analysis/notification_navigation_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_navigation_test.dart
@@ -664,7 +664,7 @@ main() {
     var libFile = addFile('$projectPath/bin/lib.dart', libCode);
     addTestFile('part of lib;');
     return prepareNavigation().then((_) {
-      assertHasRegionString('part of lib');
+      assertHasRegionString('lib');
       assertHasFileTarget(libFile, libCode.indexOf('lib;'), 'lib'.length);
     });
   }