widget in accel.group that causes
accel.signal to be emitted if the accelerator is activated.
The accel.group needs to be added to the widget's toplevel via
gtkWindowAddAccelGroup, and the signal must be of type G_RUN_ACTION.
Accelerators added through this function are not user changeable during
runtime. If you want to support accelerators that can be changed by the
user, use gtkAccelMapAddEntry and gtkWidgetSetAccelPath or
gtkMenuItemSetAccelPath instead.gtkWidgetAddAccelerator(object, accel.signal, accel.group, accel.key, accel.mods, accel.flags)objectaccel.signalaccel.groupaccel.keyaccel.modsaccel.flagsGTK_ACCEL_VISIBLE