Wrong holiday date for Venice

[remixtj]

For Venice, Italy, April 25th is added as specific Holiday for the city. This is not correct, since is already holiday because it's a national-wide festivity.

The correct day for Venice, since the creation of the 25th of April as nation-wide holiday, is November 21st, Festa della Madonna della Salute (source: https://it.wikipedia.org/wiki/Festa_della_Madonna_della_Salute#A_Venezia)

[KJhellico]

@remixtj, thank you for your suggestion! As I understand, this is the same as for Latina and Pordenone, which also have St. Mark as their patron saint.