\Drupal\Core\Entity\EntityStorageInterface::loadMultiple() and ::resetCache() incorrectly updated to

I've changed it to

 @param mixed[]|null $ids

to match EntityStorageInterface::load() - if we want to not have this as mixed then we need to be consistent and fix this for the the $id and $ids on the interface.

@param array<string|int>|null $ids is what the other MR does, and that's the more PHPStan-like syntax, and also is more descriptive than just mixed[]

Yeah but we should update all the id / ids on the interface - the interface should be consistent with itself.

I'll close this as a dupe and comment over there.