Add box to extended page type box

[frozzare]

It would be nice to add a property to a box that exists on the page type class that you extended. How this should work isn't thought of yet. Maybe it could use the same box method and add properties last in the box if the box exists.

Example:

class Simple_Content_Page_Type extends Papi_Page_Type {

  public function register() {
    $this->box( 'Content', [
       papi_property()
    ] );
  }

}

class Article_Page_Type extends Simple_Content_Page_Type {

  public function register() {
    // Add a property last in `Content` box.
    $this->box( 'Content', [
       papi_property()
    ] );
  }

}

[frozzare]

This is added in 2.5.0 and you can extended multiplied page types 👍