there's no tail in the match anymore

MarkdownSharp/Markdown.cs

@@ -1458,11 +1458,11 @@ private static string handleTrailingParens(Match match)
  // the google link to not be matched again.
  if (match.Groups[1].Success)
  return match.Value;
+
  var protocol = match.Groups[2].Value;
  var link = match.Groups[3].Value;
- var tail = match.Groups[4].Value;
  if (!link.EndsWith(")"))
- return "<" + protocol + link + ">" + tail;
+ return "<" + protocol + link + ">";
  var level = 0;
  foreach (Match c in Regex.Matches(link, "[()]"))
  {
@@ -1478,9 +1478,10 @@ private static string handleTrailingParens(Match match)
  level--;
  }
  }
+ var tail = "";
  if (level < 0)
  {
- link = Regex.Replace(link, @"\){1," + (-level) + "}$", m => { tail = m.Value + tail; return ""; });
+ link = Regex.Replace(link, @"\){1," + (-level) + "}$", m => { tail = m.Value; return ""; });
  }
  return "<" + protocol + link + ">" + tail;
  }