* 3.4: (83 commits)
add missing version attribute
Show exception is checked twice in ExceptionController of twig
allow SSI fragments configuration in XML files
Display a better error message when the toolbar cannot be displayed
[SecurityBundle] Add user impersonation info and exit action to the profiler
render hidden _method field in form_rest()
Add Doctrine Cache to dev dependencies to fix failing unit tests.
return fallback locales whenever possible
Fix Predis client cluster with pipeline
[Dotenv] Test load() with multiple paths
[Console] Fix catching exception type in QuestionHelper
Improved the exception page when there is no message
[WebProfilerBundle] Eliminate line wrap on count columnt (routing)
[Profiler][Validator] Add a validator panel in profiler
[Validator] replace hardcoded service id
[Routing] Fix XmlFileLoader exception message
Remove duplicate changelog entries
[DI] Dedup tags when using instanceof/autoconfigure
[Translation] Fix FileLoader::loadResource() php doc
[Serializer] Fix workaround min php version
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