change in IO error messages

In the 20021021 release candidate, a newline is now appended to IO error messages, including in particular the case of (ioError (userError "user message")). I dislike this change for several reasons: * It treats IO errors differently from other exceptions. That is, (show e) for an Exception e has a newline appended for IO errors but not other exceptions. * It introduces an unnecessary inconsistency with GHC. * It breaks HUnit, which needs to manipulate error message strings. -- Dean