* 3.1:
[TwigBridge] fix tests
Tag the FormFieldRegistry as being internal
[Form] Fix Date\TimeType marked as invalid on request with single_text and zero seconds
[FrameworkBundle] Register the ArrayDenormalizer
[Serializer] Fix DataUriNormalizer's regex
[Validator] Added missing swedish translation
[TranslationDebug] workaround for getFallbackLocales.
[Translation] fixed nested fallback catalogue using multiple locales.
fixed phpdoc
[Command] Fixed method comments as phpDoc syntax
Added single quotes for upgrade guides.