code: def wheelEvent(self, event):
          
          # This feature is disabled on MacOS, see Issue 1510
          if sys.platform != 'darwin':
              if event.modifiers() & Qt.ControlModifier:
                  if hasattr(event, 'angleDelta'):
                      if event.angleDelta().y() < 0:
                          self.zoom_out.emit()
                      elif event.angleDelta().y() > 0:
                          self.zoom_in.emit()
                  elif hasattr(event, 'delta'):
                      if event.delta() < 0:
                          self.zoom_out.emit()
                      elif event.delta() > 0:
                          self.zoom_in.emit()
                  return
          QPlainTextEdit.wheelEvent(self, event)
          self.highlight_current_cell()
docs: Reimplemented to emit zoom in/out signals when Ctrl is pressed