manifest: improve error message about newlines in filenames

Include the offending filenames in the error message.  Now this error message
is consistent with the same error issued by dirstate.py (although there is
still duplicate code).

mercurial/manifest.py

@@ -125,7 +125,7 b' class manifest(revlog.revlog):'
             for f in l:
                 if '\n' in f or '\r' in f:
                     raise error.RevlogError(
-                        _("'\\n' and '\\r' disallowed in filenames"))
+                        _("'\\n' and '\\r' disallowed in filenames: %r") % f)
 
         # if we're using the listcache, make sure it is valid and
         # parented by the same node we're diffing against