Kernighan was a co-author of the Go book, but I don't know how much he was involved with the actual design of the language. Maybe not much, or at all, although, of course, he is a key part of the original Unix mafia (my term, not pejorative, rather meant admiringly, because I cut my programming teeth on UNIX and C software and books, and worked on that platform a lot, earlier), many of whom are still going strong in their 70s and 80s. So the Go bracket style may not be attributable to him.