Fix tool URL for generating spec link - now 0.25

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 19be5f0..2bcb4c3 100644
--- a/pkgs/markdown/tool/common_mark_stats.dart
+++ b/pkgs/markdown/tool/common_mark_stats.dart
@@ -59,7 +59,7 @@
       var actual = parseFragment(output);
       nestedMap[e.example] = compareHtml(expected.children, actual.children);
       if (verbose && !nestedMap[e.example]) {
-        print('FAIL: http://spec.commonmark.org/0.24/#example-${e.example}');
+        print('FAIL: http://spec.commonmark.org/0.25/#example-${e.example}');
         print('input:');
         print(indent(e.markdown));
         print('expected:');