Inconsistent highlighting of "void"

[roblourens]

Reported in microsoft/vscode#120954

As a return type, void is support.class.php while string is storage.type.php

Is this as expected? I have no idea.

Original steps:

Steps to Reproduce:

1. Create a new .php file
2. Paste the following code

<?php
class MyClass
{
  public static function methodA() : void
  {
  }

  public static function methodB() : string
  {
      return "I'm a string";
  }
}

3. Check the editor tokens and scopes
   

You will see that the void type declaration is hightlighted as a support.class. I understand that it is a keyword, like string, int and others, not a class.

---

Also noticed that it's inconsistent here:

<?php

/**
 * @param void $x
 */
function a($x): void {
	return '';
}