fix type annotations for InputValidator

[shmax]

Fixing another type annotation (to make static type checkers such as PHPStan happy). In this case, changing CodeDefinition::optionValidator and CodeDefinitionBuilder::optionValidator from type InputValidator to array[string]InputValidator.

Note: I validated this PHPDoc annotation syntax using PHPStan, and also this linter

[shmax]

@jbowens Hate to bother you, but when you get a chance I'd appreciate a review...

[jbowens]

@shmax cool, thanks for the change

[shmax]

Thanks! Would you mind doing a tiny release so I can get the changes?

[shmax]

Wonderful, thank you!