Add @method PhpDoc for EntityStorageInterface descendants

Problem/Motivation

With the current typehinting an IDE can't provide proper autocompletions for methods and other inspections.

Steps to reproduce

class C1 {
  protected \Drupal\node\NodeStorageInterface $nodeStorage;

  public function m1() {
    foreach ($this->nodeStorage->loadMultiple() as $node) {
      $node->isPromoted();
    }
  }
}

Proposed resolution

Add @method PhpDoc entries for every EntityStorageInterface descendants.