Thread:Support/Change Author extension

I've found this extension yesterday and looked at some of its translations and I noticed something there: The extension currently uses different messages when you change only one author and when you change multiple authors (,, and . I don't think that should be done, because plural rules differ from language to language. When the plural in English is used, some languages might still be at the singular. Also, in the messages I think singular/plural actually doesn't matter at all, the people will get it like that. Thus, I'd solely use  and  when changing an author (and remove plural there).