Salvador's presence in this list might be less puzzling to some (like me, before I looked it up) if you entered its full name: "São Salvador da Bahia de Todos os Santos".
So, at the moment, I dont speak any Spanish or Portuguese, so I had to translate most of these answers. Google translate says that santo means holy and not saint.
I think having researched it a bit, 'Santo' is the more formal word used in male saints' names in Spanish, usually abbreviated to San except where the name starts in To- or Do-. It disambiguates if there were, for instance, to be a saint called Mingo (Santo Mingo/ San Domingo) - Santo Domingo is named after the historical personage known in English as St Dominic.