Add support for static private members

[mikeconley]

In #174, support was added for static class methods. Great! This ticket is about adding support for static private members.

I have a class like this:

class Thing {
  /**
   * The static Thing singleton instance.
   *
   * @static
   * @private
   * @type {Thing|null}
   */
  static private #instance = null;

  // ...
}

:private-members: doesn't show the property by default. Using .. js:autoattribute:: Thing#instance, I expect the property to appear in the docs with decoration indicating that it's both static (and in this case, private).

It does appear in the generated doc, but doesn't show the static keyword nor any indication that the member is private.