Support for nullsafe function call syntax

Description

The following code:

<?php
class Foo {
    public function __invoke(): string {
        return 'foo invoked';
    }
}

$f = new Foo();
var_Dump($f());

results in this expected output:

string(11) "foo invoked"

$g = null;
$g();

results in this expected output

Fatal error: Uncaught Error: Value of type null is not callable

$g = null;
$g?->__invoke();

results in this expected output:

string(11) "foo invoked"

As the call to ->__invoke() can be shortened to () I would have expected to be able to use the nullsafe operator here as well and write

$g = null;
$g?();

But this results in in this output:

Parse error: syntax error, unexpected token ")"

I would have expected

string(11) "foo invoked"

Is this on purpose? I could not find any mention of invoke in the RFC. So was this overseen?

See also https://3v4l.org/n09i2

PHP Version

All currently supported PHP-Versions

Operating System

No response

Reproduce the reported behavior using the PHP snippets in the issue, then read the linked nullsafe operator RFC and the existing implementation and tests for nullsafe calls. Done means determining and implementing the intended handling of $g?() while preserving the documented errors for ordinary calls and matching the expected behavior.