there are two possible marriages for Johanna in the right area, at about the right time - both with possible cross matches :
Name: Johanna M'Cormack
Registration district: Thomastown
Event type: Marriage
Quarter and year: Oct-Dec 1906
Volume : 4 / Page : 331
Name : Michael Ryan
[same references as Johanna 1]
Name: Johanna M'Cormack
Registration district: Thomastown
Event type: Marriage
Quarter and year: Jan-Mar 1907
Volume : 4 / Page : 452
Name : Michael Ryan
[same references as Johanna 2]
There's no guarantee with index cross-matches, but since McCormack is not that common a surname in Kilkenny it seems likely that one of these marriages is your family.
see :
Details included on a Marriage CertShane