Support template generics in PSALM class inheritance

Originally requested in https://github.com/klesun/deep-assoc-completion/issues/162#issuecomment-675152123

Quoting @zmitic:

There is one minor issue, probably irrelevant. Because of nested-set requiring its own parent repository (not one from example under), I put code in trait like this:

class CityRepository extends ServiceEntityRepository
{
    /** @use RepositoryUtilsTrait<City> */
    use RepositoryUtilsTrait;

    public function __construct(ManagerRegistry $registry)
    {
        parent::__construct($registry, City::class);
    }
}

Trait itself:

    /**
     * @return ?T
     */
    public function getOneResultOrNull(Generator ...$generators)
    {
       // ...
    }

No results:

klesun / deep-assoc-completion

Support template generics in PSALM class inheritance #164