ShortcutAction.parseString

Tries to parse the given string into an action.

On success, the parsed action is returned. When parsing failed, null is returned.

The accepted strings are:

• nothing, for [gtk.nothing_action.NothingAction]
• activate, for [gtk.activate_action.ActivateAction]
• mnemonic-activate, for [gtk.mnemonic_action.MnemonicAction]
• action(NAME), for a [gtk.named_action.NamedAction] for the action named NAME
• signal(NAME), for a [gtk.signal_action.SignalAction] for the signal NAME