[FEATURE] Support for single-expression (braceless) functions

[Starexify]

In haxe, we can do this to have only a single expression from a function, without needing to encapsulate it within braces {} :

public static function get_y() return 1; // <-- errors here in polymod

static function main() {
  trace(get_y());
}

And in a haxe environment it would return:

1

But in polymod, we get this:

ERROR  Error while parsing script assets/scripts/WorstCParser.hxc#5: EUnexpected
Unexpected error: Unexpected token ";", is there invalid syntax on this line?