Update German translation. Still 690 to go.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23479 57a11ea4-9604-0410-9ed3-97b8803252fd
Fix ugly typo in string.

I know, this is a minor break of string freeze, but it's still a very
hidden string, so I fix the typo better now than later.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23480 57a11ea4-9604-0410-9ed3-97b8803252fd