Document multi ambiguity between int and uint
Document multi ambiguity between int and uint

As veesh++ points out, multis cannot distinguish between `int` and `uint`
any more than they can distinguish between `int and `int64`.

MasterDuke17/doc,tbrowder/doc,tbrowder/doc,tbrowder/doc,MasterDuke17/doc,perl6/doc,perl6/doc,perl6/doc,perl6/doc,tbrowder/doc,MasterDuke17/doc,perl6/doc,MasterDuke17/doc