Added Swedish language

[Sopor]

I'm not a macOS user so bear with me if i made some mistake. Some strings should be easier to translate with some kind of context. If you find any errors or if you think you can improve it, you are free to do so.

[rxhanson]

Thanks!!

[Sopor]

@rxhanson I noticed that you changed sv-SE to sv.

In Finland they speak Swedish too and to separate these two you use sv-SE instead of only sv. Finnish locale is sv-FI.

There are differences in linguistics and vocabulary between them (how much i don't know). Currency, telephone codes, and stuff like that are also different.

You do have pt-BR and pt-PT, so why not sv-SE? Doesn't macOS has sv-SE and sv-FI locales?

[rxhanson]

Ah, sorry. When I added the localization, for some reason sv was all that popped up. Upon further inspection, there are all of the additional locales. I went ahead and changed it back to sv-SE. With just sv, I think it would have just used this localization for all the Swedish ones, which isn't that bad because it would prompt Swedish speaking users from other locales to contribute (based on other localizations I've had :). Either way, best to have it be your intended locale.