The Multishipping::beforeSetShippingMethods() method has a wrong PHPDoc return type

https://github.com/magento/magento2/blob/c58d2d/app/code/Magento/GiftMessage/Model/Type/Plugin/Multishipping.php#L32-L45

Should be:

@return void

https://github.com/magento/magento2/issues/3340

See also: