Fix doctoring in `MapDatasetOnOff.fake`
@@ -2365,6 +2365,8 @@ class MapDatasetOnOff(MapDataset):
Parameters
----------
+ npred_background : `~gammapy.maps.Map`
+ Expected number of background counts in the on region
random_state : {int, 'random-seed', 'global-rng', `~numpy.random.RandomState`}
Defines random number generator initialisation.
Passed to `~gammapy.utils.random.get_random_state`.
