Updated the Swedish language file

[Magnus_Johansson]

Hey all! I have just revised, updated and corrected  the Swedish language file for Piano Booster.

Regards,
Magnus Johansson

[jackth]

Usually with Github, one would check out the branch/fork that he/she wishes to merge, then update the code (such as with your translations).  Once tested, the change is pushed to Github, and a pull request can be created on the corresponding branch/fork.

[Magnus_Johansson]

I can't find my translation revision in the source code of Piano Booster or in any of its forks. I can only find it in Weblate: https://hosted.weblate.org/projects/pianobooster/