Symfony deprecations

[dannyvw]

Method "Symfony\Component\DependencyInjection\Extension\Extension::getAlias()" might add "string" as a native return type declaration in the future. Do the same in child class "Exercise\HTMLPurifierBundle\DependencyInjection\ExerciseHTMLPurifierExtension" now to avoid errors or add an explicit @return annotation to suppress this message.

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Method "Symfony\Component\Config\Definition\ConfigurationInterface::getConfigTreeBuilder()" might add "TreeBuilder" as a native return type declaration in the future. Do the same in implementation "Exercise\HTMLPurifierBundle\DependencyInjection\Configuration" now to avoid errors or add an explicit @return annotation to suppress this message.

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Method "Symfony\Component\HttpKernel\CacheWarmer\WarmableInterface::warmUp()" might add "array" as a native return type declaration in the future. Do the same in implementation "Exercise\HTMLPurifierBundle\CacheWarmer\SerializerCacheWarmer" now to avoid errors or add an explicit @return annotation to suppress this message.

[easis]

Also:
[2021-12-02T15:15:48.146072+01:00] php.INFO: User Deprecated: Method "Twig\Extension\ExtensionInterface::getFilters()" might add "array" as a native return type declaration in the future. Do the same in implementation "Exercise\HTMLPurifierBundle\Twig\HTMLPurifierExtension"

[HeahDude]

v4.0 has just been tagged. Thank you for your patience.