Fix german translation

1) The old translation was rather bad.
2) The new format matches the default format. Since this is a file that
   is shipped with the application the default formats should match.
3) The old format wouldn't work out of the box, because there is no such
   style as 'german'. So better use the default style, though.

A better diff in my opinion is against format/default.

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I'm a native german speaker ;)