Update the text displayed in the menu entry.

def _update_show_toolbars_action(self):
        """Update the text displayed in the menu entry."""
        if self.toolbars_visible:
            text = _("Hide toolbars")
            tip = _("Hide toolbars")
        else:
            text = _("Show toolbars")
            tip = _("Show toolbars")
        self.show_toolbars_action.setText(text)
        self.show_toolbars_action.setToolTip(tip)