activate
For widgets that can be “activated” (buttons, menu items, etc.), this function activates them.
The activation will emit the signal set using method@Gtk.WidgetClass.set_activate_signal during class initialization.
Activation is what happens when you press Enter on a widget during key navigation.
If you wish to handle the activation keybinding yourself, it is recommended to use method@Gtk.WidgetClass.add_shortcut with an action created with ctor@Gtk.SignalAction.new.
If @widget isn't activatable, the function returns false.
Return
true if the widget was activatable