Do not send signature help inside of callback args on requests

[RblSb]

Probably related to: https://github.com/HaxeFoundation/haxe/blob/development/src/typing/typerDisplay.ml#L199

class Main {
	static function main() {
		foo(0, (name, age) -> {});

		foo(0, (name, age) -> {
			final f = (a, b, c) -> {}
			f(1, 2, 3); // type this line to see signature for `foo` after `;`
			// or just type here `,` to see same useless signature that blocks your view
		});
	}

	/** Foo **/
	static function foo(
		a:Int,
		?cb:(name:String, age:Int) -> Void,
		?b:Int,
		?c:Int,
	):Void {}
}