TaxonomyLoadTree incorrectly has array return type hint

[Kingdutch]

Problem

The TaxonomyLoadTree::resolve method has an array typehint. However, it actually returns an instance of Deferred. This causes the exception Return value of Drupal\graphql\Plugin\GraphQL\DataProducer\Taxonomy\TaxonomyLoadTree::resolve() must be of the type array, object returned to be thrown.

Solution

Change the typehint to ?Deferred to match the PHPDoc comment.