def number_of_spaces
      todo.character_number - 1 - (todo.line.length - todo.line.lstrip.length)
    end
def number_of_spaces
      todo.character_number - 1 - (todo.line.length - todo.line.lstrip.length)
    end
How many spaces before the carets should there be?
 @return [Fixnum]
 @api private