[FEATURE] Support for get and set functions

[KoloInDaCrib]

Fixes FunkinCrew/Funkin#3781

Doesn't have any other PR that has to be merged in order to work, hooray!!!

for getting the variable, the words supported are "get", "null" and everything else (i.e. "default")
for setting the variable, the words supported are "set", "never", "null" and everything else (i.e. "default")

also uhh haven't had the chance to test this that much so like if you want to uh test it yourself n stuff

[AbnormalPoof]

Trying to review this but I don't think it's compiling properly...

ERROR  /Volumes/THE HOLE/FNF STUFF/FNF Repos/Funkin-Base/.haxelib/polymod/git/polymod/hscript/_internal/PolymodInterpEx.hx:286: characters 29-37

286 |        var v = fop(expr(e1),expr(e2));
    |                             ^^^^^^^^
    | Too many arguments

ERROR  /Volumes/THE HOLE/FNF STUFF/FNF Repos/Funkin-Base/.haxelib/polymod/git/polymod/hscript/_internal/PolymodInterpEx.hx:302: characters 33-36

302 |   return super.evalAssignOp(op, fop, e1, e2);
    |                                 ^^^
    | (Dynamic -> Dynamic) -> Dynamic should be (Dynamic, Dynamic) -> Unknown<0>
    | For function argument 'fop'

ERROR  /Volumes/THE HOLE/FNF STUFF/FNF Repos/Funkin-Base/.haxelib/polymod/git/polymod/hscript/_internal/PolymodInterpEx.hx:274: characters 20-32

274 |  override function evalAssignOp(op:String, fop:(Dynamic->Dynamic)->Dynamic, e1:Expr, e2:Expr)
    |                    ^^^^^^^^^^^^
    | Field evalAssignOp overrides parent class with different or incomplete type

     ->  /Volumes/THE HOLE/FNF STUFF/FNF Repos/Funkin-Base/.haxelib/hscript/git/hscript/Interp.hx:152: characters 11-23

     152 |  function evalAssignOp(op,fop,e1,e2) : Dynamic {
         |           ^^^^^^^^^^^^
         | Base field is defined here

         | error: (Dynamic -> Dynamic) -> Dynamic should be (Dynamic, Dynamic) -> Unknown<0>
         | have: (..., (..., ...) -> ..., ..., ...) -> ...
         | want: (..., ... -> ..., ..., ...) -> ...

[AbnormalPoof]

holy shit peak PR:

var test(get, set):Bool;
var _test:Bool = false;

function get_test():Bool {
  trace("TEST");
  return _test;
}

function set_test(value) {
  trace("TEST");
  _test = value;
}

public function new()
{
  trace(test);
  test = true;
  trace(test);
}

hscriptClass(assets/test.hxc):32: TEST
hscriptClass(assets/test.hxc):49: false
hscriptClass(assets/test.hxc):37: TEST
hscriptClass(assets/test.hxc):32: TEST
hscriptClass(assets/test.hxc):51: true