Sets the text of @self.
If [property@Gtk.CheckButton:use-underline] is %TRUE, an underscore in @label is interpreted as mnemonic indicator, see [method@Gtk.CheckButton.set_use_underline] for details on this behavior.
The text shown next to the indicator, or %NULL to show no text
See Implementation
Sets the text of @self.
If [property@Gtk.CheckButton:use-underline] is %TRUE, an underscore in @label is interpreted as mnemonic indicator, see [method@Gtk.CheckButton.set_use_underline] for details on this behavior.