docs: def split(self):
          """
          Split the code editor widget, return a clone of the widget ready to
          be used (and synchronised with its original).
  
          Splitting the widget is done in 2 steps:
              - first we clone the widget, you can override ``clone`` if your
                widget needs additional arguments.
  
              - then we link the two text document and disable some modes on the
                  cloned instance (such as the watcher mode).
          """
          # cache cursor position so that the clone open at the current cursor
          # pos
          l, c = TextHelper(self).cursor_position()
          clone = self.clone()
          self.link(clone)
          TextHelper(clone).goto_line(l, c)
          self.clones.append(clone)
          return clone