Gtk.ToggleButton.new_with_mnemonic

function new_with_mnemonic(label:String):Gtk.Widget {
    // Gjs wrapper for gtk_toggle_button_new_with_mnemonic()
}

Creates a new Gtk.ToggleButton containing a label. The label will be created using Gtk.Label.new_with_mnemonic, so underscores in label indicate the mnemonic for the button.