anchor.diff:    "video",
     "wbr"
   ];
  +
   final RegExp nonHTML =
       new RegExp("</?(?!(${validHtmlTags.join("|")})[> ])\\w+[> ]");
   
  
positive.code: // warn about them.
  // Covers anything with leading digits/symbols, empty string, weird punctuation, spaces.
  final RegExp notARealDocReference = new RegExp(r'''(^[^\w]|^[\d]|[,"'/]|^$)''');
  
  final List<md.InlineSyntax> _markdown_syntaxes = [
    new _InlineCodeSyntax(),
  
negative.code:   @override
    bool onMatch(md.InlineParser parser, Match match) {
      var url = match[1];
      var text = htmlEscape.convert(url).replaceFirst(_hide_schemes, '');
      var anchor = new md.Element.text('a', text);
      anchor.attributes['href'] = url;
      parser.addNode(anchor);
  