Fixed wrong Content-Length header when sending file using Response::sendContentAsFile().

Docs guide structure fix [ci skip]

fixes #7013

Fixing the application config widget registration after the #6991 fix

[skip ci] Create russian translation of output-pagination.md

[skip ci] Create russian translation of output-sorting.md

Odd symbol in meta tag [skip ci]

it is already mentioned in design decisions file.

Odd symbol in meta tag

There is no needed the "/" before closing.

Enh #6857: Added `yii\gii\Module::$ignoreTables` that allows you to ignore tables during model generation using `*` (reverted from commit e562f8e4)

Fixes #6852: Added `yii\helpers\BaseHtmlPurifier::helpers()` in order to be able to configure `HtmlPurifier` helper globally via subclassing

Enh #6857: Added `yii\gii\Module::$ignoreTables` that allows you to ignore tables during model generation using `*`

Makes it possible for classes that extend yii\web\ErrorHandler to provide their own informational URLs for types/classes/methods.

Fixed #6978: Dependency Injection Container not reset when destroying application in functional tests

Docs internals ja reviewed [ci skip]

docs/internals/core-code-style.md - removed a duplicated block [ci skip]

Docs guide start small fixex [ci skip]

docs/guide-ja/start-* refined [ci skip]

style guide examples should follow its own rules

example code suffering from a double case of else-after-return simplified according to the subsequent rule