fix typo in phpdoc of yii\redis\Connection [skip ci]

[skip ci] Added missing translation in Polish

fix link [skip ci]

migration fixed

[skip ci][UK][Guide] intro

Remove double "the"

Allow single items to choose their encoding option.

[skip ci] Translation of docs to russian (structure-widgets section)

Added Security::generateRandomHexKey(), used it for various tokens and default key generation

Fixes #4114: Added Security::generateRandomHexKey(), used it for various tokens and default key generation

fileinfo is not a hard dependency.

[skip-ci] Advanced app `User` model code style fixes

\yii\rbac\PhpManager adjustments