make it explicit that hex, binary and octal literals are all UInts

For novices, it might be easy to miss that 0x1, 0o1 and 0b1
are all represented in the same type (Uint8),
therefore the output of such values is always formatted
as a hexadecimal number. This change makes that more explicit.
Merge pull request #4660 from waldir/patch-1

make it explicit that hex, binary and octal literals are all Uints