2516: Argument for @NotNull parameter 'psiDirectory' fix

[vitaliyboykocontributor]

Description (*)

Fixed Issues (if relevant)

1. Fixes magento/magento2-phpstorm-plugin#2516

Questions or comments

Contribution checklist (*)

• [ ] Pull request has a meaningful description of its purpose
• [ ] All commits are accompanied by meaningful commit messages
• [ ] All new or changed code is covered with integration/functional tests (if applicable)
• [ ] All automated tests passed successfully (all builds are green)