The Internationalization guide is not up2date in regards to 3.x changes.

The ezpublish global has been renamed to "ezplatform"

So, for instance

+\{% for lang in ezpublish.availableLanguages %}
-\{% for lang in ezplatform.availableLanguages %}

Also, `ezpublish` service is no longer public so services like RouteReferenceGenerator and TranslationHelper needs to be injected explicit.