Minor fixes.

pkg/front_end/lib/src/fasta/parser/listener.dart

Index: pkg/front_end/lib/src/fasta/parser/listener.dart
diff --git a/pkg/front_end/lib/src/fasta/parser/listener.dart b/pkg/front_end/lib/src/fasta/parser/listener.dart
index 174b4def0bba095c59db0730559c365392b766f6..d89bb75414d611544221540d562b340bc5933d5b 100644
--- a/pkg/front_end/lib/src/fasta/parser/listener.dart
+++ b/pkg/front_end/lib/src/fasta/parser/listener.dart
@@ -484,6 +484,7 @@ class Listener {
   void beginPartOf(Token token) {}
 
   /// Handle the end of a "part of" directive.  Substructures:
+  /// - Metadata
   /// - Library name (a qualified identifier)
   void endPartOf(Token partKeyword, Token semicolon) {
     logEvent("PartOf");