G-IR currently lacks an annotation for associating async calls to their
_finish counterparts. As a result, vala's binding generator assumes that
corresponding function is just function name - _async + _finish. This
holds true for 99% of the time, but not here, because
nm_device_wifi_request_scan_options_async uses
nm_device_wifi_request_scan_finish instead of expected
nm_device_wifi_request_scan_options_finish (sharing it with
nm_device_wifi_request_scan_async). As such, a metadata entry is
required to point vala to correct finishing function.
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1114
(cherry picked from commit c0e31c7a70)
