Issue #3044734: Automated coding standards fixes

src/Component/Helper/FillPdfMappingHelper.php

src/Component/Utility/FillPdf.php

src/Controller/HandlePdfController.php

src/Entity/FillPdfForm.php

src/FillPdfLinkManipulatorInterface.php

src/Form/FillPdfFormConfirmFormBase.php

src/Form/FillPdfFormForm.php

src/Form/FillPdfOverviewForm.php

src/Form/FillPdfSettingsForm.php

src/OutputHandler.php

src/OutputHandlerInterface.php

src/Plugin/FillPdfActionPlugin/FillPdfSaveAction.php

src/Plugin/PdfBackend/FillPdfServicePdfBackend.php

src/Plugin/PdfBackend/LocalServerPdfBackend.php

src/Plugin/PdfBackend/PdftkPdfBackend.php

src/Serializer.php

src/Service/BackendProxy.php

src/Service/FillPdfLinkManipulator.php

src/TokenResolver.php

tests/src/Functional/FillPdfFormFormTest.php