docs/guide/input-forms.md - small fix [ci skip]

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

Yii2 basic code coverage added

Fixes #6404: advanced application template `Alert` widget was generating duplicate IDs in case of multiple flashes

/docs/guide-ja/db-migrations.md added [ci skip]

[skip ci] Fix grammatical error

Deleted double tip [skip ci]

Update tutorial-advanced-app.md

Typo fixes

may happen if yii is installed globally.

fixes #6402

/docs/guide-ja/db-active-record.md added [ci skip]

/docs/guide/db-active-record.md small fixes [ci skip]

fixes #5975