Correction of many errors code inspection.
Adjustments code according to the standards.
Adding missing PHPDoc comment.
Update error.php
Update error.php
Merge pull request #3138 from thiagotalma/inspections

Correction of many warnings code inspection.
Added `$user` as the first parameter of `yii\rbac\Rule::execute()`
Fixes test break.
Fixes #3129: added RBAC documentation.
Merge branch 'master' of https://github.com/yiisoft/yii2