spanish docs Events
Merge pull request #6390 from larnu/spanish_docs

spanish docs Events [skip ci]
Add File API detection to client file validator

Fixes #6345
Fixes #6381: Client-side file validation should be disabled if the browser does not support it
Fixes #5494: Added support for specifying a menu header as a configuration array in `yii\bootstrap\Dropdown`
Fixes #5005: Added support to suppress loading the same CSS files in AJAX responses