fix wording in script

pkgs/markdown/tool/common_mark_stats.dart

diff --git a/pkgs/markdown/tool/common_mark_stats.dart b/pkgs/markdown/tool/common_mark_stats.dart
index 1a10ad4..d76003c 100644
--- a/pkgs/markdown/tool/common_mark_stats.dart
+++ b/pkgs/markdown/tool/common_mark_stats.dart
@@ -13,7 +13,7 @@
 
 const _commonMarkTests = 'common_mark_tests.json';
 
-// Locate the "test" directory. Use mirrors so that this works with the test
+// Locate the "tool" directory. Use mirrors so that this works with the test
 // package, which loads this suite into an isolate.
 String get _currentDir => p
     .dirname((reflect(main) as ClosureMirror).function.location.sourceUri.path);