the function ToTextSpan needs to be modified as follows:

    public static TextSpan ToTextSpan(IToken token)
    {
        if (token == null)
            return new TextSpan();

        string tokentext = token.Text ?? string.Empty;
        if (token.Text.Equals("\n") || token.Text.Equals("\r\n"))
            tokentext = string.Empty;

        return new TextSpan()
        {
            iStartLine = token.Line - 1,
            iStartIndex = token.CharPositionInLine,
            iEndLine = token.Line - 1,
            iEndIndex = token.CharPositionInLine + tokentext.Length
        };
    }