Docblock Fixes

These fixes were generated by enabling all existing and upcoming phpdoc fixes in php-cs-fixer from this pull request: [PHP-CS-Fixer#887](https://github.com/FriendsOfPHP/PHP-CS-Fixer/pull/887). Also, the `@var` changes were introcuded by [PHP-CS-Fixer#841](https://github.com/FriendsOfPHP/PHP-CS-Fixer/pull/841).