hex literals for unsigned ints, sized by digits

[StefanKarpinski]

Usually when you use hex notation for numbers, you are trying to create an unsigned value with a particular bit pattern. To facilitate that, it has been proposed that 0x hex integer literals represent unsigned integers of size determined by the number of digits:

• hex literals with 1-2 digits create Uint8 values
• hex literals with 3-4 digits create Uint16 values
• hex literals with 5-8 digits create Uint32 values
• hex literals with 9-16 digits create Uint64 values

This proposal would make leading zeros meaningful for hex literals, but only in that they affect the storage size of the resulting value, never its numeric value, which seems acceptable and intuitive.