Fixes #6404: advanced application template `Alert` widget was generating duplicate IDs in case of multiple flashes
Fixes #6372. [skip ci]
added code coverage ti yii2_basic
doc fix
fixed docs
Merge pull request #6455 from Ragazzo/yii2_basic_code_coverage_added

Yii2 basic code coverage added
docs/guide-ja/input-forms.md - started translation [ci skip]
docs/guide-ja/input-forms.md - completed [ci skip]
docs/guide-ja/README.md - updated [ci skip]
Merge pull request #6456 from softark/docs-guide-ja-input-forms

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