Updated sl_SI to new format.

While there aren't a lot of translations updated yet, I'd like to throw this out there. The following keys contain the "Equivalent Exchange 3" string that's not supposed to be translated:
```
command.ee3.particles.turned_on
command.ee3.particles.turned_off
command.ee3.sounds.set_to_all
command.ee3.sounds.set_to_self
command.ee3.sounds.turned_off
itemGroup.EE3
version.current
```
I'd suggest to replace them with %s and pass it as an argument.