Sets the "action" and possibly the "target" attribute of this.
The format of detailed_action is the same format parsed by
parse_detailed_name.
See set_action_and_target or set_action_and_target_value for more flexible (but slightly less convenient) alternatives.
See also set_action_and_target_value for a description of the semantics of the action and target attributes.
| this |
a MenuItem |
| detailed_action |
the "detailed" action string |