anchor.diff:          _extractAllDocs(
               errorClass.name, cfeToAnalyzerErrorCodeTables.analyzerCodeToInfo);
           // Note: only one error class has the `includeCfeMessages` flag set;
  -        // verify_diagnostics_test.dart verifies this.  So we can safely break.
  +        // verify_diagnostics_test.dart verifies this. So we can safely break.
           break;
         }
       }
  
positive.code: /// Generate the file `diagnostics.md` based on the documentation associated
  /// with the declarations of the error codes.
  void main() async {
    IOSink sink = File(computeOutputPath()).openWrite();
    DocumentationGenerator generator = DocumentationGenerator();
    generator.writeDocumentation(sink);
    await sink.flush();
    await sink.close();
  
negative.code: [meta-visibleForOverriding]: https://pub.dev/documentation/meta/latest/meta/visibleForOverriding-constant.html
  [meta-visibleForTesting]: https://pub.dev/documentation/meta/latest/meta/visibleForTesting-constant.html
  ''');
      var errorCodes = infoByName.keys.toList();
      errorCodes.sort();
      for (String errorCode in errorCodes) {
        var info = infoByName[errorCode]!;
        if (info.hasDocumentation) {
          sink.writeln();
          info.writeOn(sink);
  