Do not mention default values in PHPDoc

[arogachev]

This seems redundant:

https://github.com/yiisoft/validator/blob/30cbd83eff595c26bca45f1b1ddcec5d2935a791/src/Rule/Boolean.php#L20

• Default value is shown in the docs, IDE also supports them.
• It adds another source of truth, so docs can be out of sync after the code changes.

It can get even worse in case of bigger data:

https://github.com/yiisoft/validator/blob/30cbd83eff595c26bca45f1b1ddcec5d2935a791/src/Rule/Ip.php#L53-L61

[samdark]

Agree. Let's remove these.