[FEATURE] Add numeric separators support

[Starexify]

So in haxe, we can use numeric separators like this:

var largeHex = 0xFF_00;
trace(largeHex);

var bigInt = 1_000_000;
trace(bigInt);

It would return:

 ERROR  Error while parsing script assets/scripts/WorstCParser.hxc#7: EUnexpected
Unexpected error: Unexpected token "_00", is there invalid syntax on this line?
 ERROR  Error while parsing script assets/scripts/WorstCParser.hxc#7: EUnexpected
Unexpected error: Unexpected token "_000_000", is there invalid syntax on this line?

But the output in a haxe environment (hxcpp, try haxe) would be this and ignore the _ from numerals:

65280
1000000

Note

Reference: https://github.com/HaxeFoundation/haxe-evolution/blob/master/proposals/0018-number-separators.md