Azerbaijani translations
Readme on "uncheck" parameter in activeCheckbox

Just a readme update.
"If you do not want any hidden input, you should explicitly set this option as null."

close #5823
minor doc adjustment [skip ci]
syntax fix [skip ci]
doc fix [skip ci]
improved translations
Merge pull request #5825 from mirjalal/master

[skip ci] improved Azerbaijani translations
Removed some badges, reodered the rest
Added phpdoc for ContentDecorator
add more default names of exceptions
Added phpdoc for Block
Fixes #5770: Added more PHP error names for `ErrorException`
Merge branch 'master' of git://github.com/yiisoft/yii2
Fixes #5833: The `message` command fails with a FK constraint error when trying to update messages
added tipp for asset registering