fixes for tool/common_mark_stats.dart

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 9d54293..2bacd18 100644
--- a/pkgs/markdown/tool/common_mark_stats.dart
+++ b/pkgs/markdown/tool/common_mark_stats.dart
@@ -6,7 +6,7 @@
 
 import 'package:args/args.dart';
 import 'package:collection/collection.dart';
-import 'package:html/dom.dart' as dom;
+import 'package:html/dom.dart';
 import 'package:html/parser.dart' show parseFragment;
 import 'package:markdown/markdown.dart' show markdownToHtml;
 import 'package:path/path.dart' as p;
@@ -39,7 +39,7 @@
   } on FormatException catch (e) {
     stderr.writeln(e);
     print(parser.usage);
-    exitCode = 64;
+    exitCode = 64; // unix standard improper usage
     return;
   }
 
@@ -100,11 +100,11 @@
   });
 
   if (raw || updateFiles) {
-    _printRaw(scores, updateFiles);
+    await _printRaw(scores, updateFiles);
   }
 
   if (!raw || updateFiles) {
-    _printFriendly(scores, updateFiles);
+    await _printFriendly(scores, updateFiles);
   }
 }
 
@@ -187,8 +187,7 @@
 }
 
 /// Compare two DOM trees for equality.
-bool compareHtml(
-    List<dom.Element> expectedElements, List<dom.Element> actualElements) {
+bool compareHtml(List<Element> expectedElements, List<Element> actualElements) {
   if (expectedElements.length != actualElements.length) {
     return false;
   }