[MLton] Specification of scan in STRING

[Vesa Karvonen]

I noticed that the specification of scan in the MLton Basis library implementation
of the STRING signature is

val scan: (Char.char, 'a) StringCvt.reader -> (string, 'a) StringCvt.reader
           ^^^^^^^^^

while the Basis spec says that it should be

val scan : (char, 'a) StringCvt.reader -> (string, 'a) StringCvt.reader
            ^^^^

Which one needs to be fixed?

-Vesa Karvonen