[display] No completion on macro instance fields

If there's a macro function on an instance, completion for that field fails with
```
Message: Invalid macro access
Code: -32603
```

For example, in the following program, completion fails when typing `m.example(`

```haxe
import haxe.macro.Expr.ExprOf;

class Main {

static function main() {
var m = new Main();
var m.example(| // expected "(param: Float) -> Any"
// get no response and an error message in vshaxe output
}

function new() { }

macro static function example(x: ExprOf, param: Float) {
trace(param);
return macro null;
}

}
```