Improve edition information for some cases

[zuphilip]

There are two types of the edition: either this is only a ordinal number like 3. or it can be a longer string like 3., überarb. Aufl.. Currently whatever is present will be printed. However, it would be better and more correct in the first case to extend this to meaningful string like 3. Aufl resp. 3. ed.. The second case can stay as it is.