v6.4.0-BETA1

Changelog (v6.3.6...v6.4.0-BETA1)

• feature symfony/symfony#51470 [FrameworkBundle][Serializer] Deprecate annotations (@alexandre-daubois)
• feature symfony/symfony#50734 [ErrorHandler] Improve fileLinkFormat handling (@nlemoine)
• feature symfony/symfony#50934 [Form] Add duplicate_preferred_choices option to ChoiceType (@arnaud-deabreu)
• feature symfony/symfony#50392 Move UriSigner from HttpKernel to HttpFoundation package (@alexander-schranz)
• feature symfony/symfony#51804 [Security] Make impersonation_path() argument mandatory and add impersonation_url() (@alexandre-daubois)
• feature symfony/symfony#50127 [TwigBridge] Add FormLayoutTestCase class (@ker0x)
• feature symfony/symfony#50030 Add new twig bridge function to generate impersonation path (@PhilETaylor)
• feature symfony/symfony#50321 [TwigBridge] Add AppVariable::getEnabledLocales() (@jmsche)
• feature symfony/symfony#51690 [Mime] Add TemplatedEmail::locale() to set the locale for the email rendering (@alexander-schranz)
• feature symfony/symfony#51543 [AssetMapper] Add support for CSS files in the importmap (@weaverryan)
• feature symfony/symfony#47715 [Form] Removing self-closing slash from <input> (@ThomasLandauer)
• feature symfony/symfony#50983 [Serializer] Deprecate annotations in favor of attributes (@derrabus)
• feature symfony/symfony#50770 [TwigBridge] Allow to change element for form_help block (@seb-jean)