docs: def goto_line(self):
          """
          Shows the *go to line dialog* and go to the selected line.
          """
          helper = TextHelper(self)
          line, result = DlgGotoLine.get_line(
              self, helper.current_line_nbr(), helper.line_count())
          if not result:
              return
          return helper.goto_line(line, move=True)