docs/guide-ja update [ci skip]

Translation guide-ja/concept-*

docs/guide-ja/output-data-providers.md - added [ci skip]

docs/guide/output-formatter.md - revised [ci skip]

docs/guide-ja/output-formatter added [ci skip]

fixes #6547
close #6482

introduced in https://github.com/yiisoft/yii2/commit/bf206efc66bc47b693271359e433679c1618189b

Fixes #3665: Improved Gii CRUD generated code to support setting initial conditions via initializing search model

Fixes #6427: In case of invalid route web application now throws exception with "Page not found" instead of "Invalid Route"

docs/guide/input-file-upload.md - revised a bit [ci skip]

/docs/guide-ja/input-file-upload.md added [ci skip]

Fixes #6434: Added `yii\behaviors\SluggableBehavior::immutable` to support keeping the generated slug unchanged