Update Resources/doc/index.rst
Update Resources/doc/index.rst

I don't see a `AnnotationRegistry::registerFile` in the `app/autoload.php` that
ships with the Symfony 2.1 standard distribution (as of
67cbb5771f38ca1ab71c83916d2fedb3c0311b16).
malarzm/DoctrineMongoDBBundle,castarco/DoctrineMongoDBBundle,alcaeus/DoctrineMongoDBBundle,tomasbro/DoctrineMongoDBBundle,juchi/DoctrineMongoDBBundle,tomasbro/DoctrineMongoDBBundle,jahller/DoctrineMongoDBBundle,0mars/DoctrineMongoDBBundle,Soullivaneuh/DoctrineMongoDBBundle,stof/DoctrineMongoDBBundle,doctrine/DoctrineMongoDBBundle,castarco/DoctrineMongoDBBundle,0mars/DoctrineMongoDBBundle,alcaeus/DoctrineMongoDBBundle,juchi/DoctrineMongoDBBundle,sarcher/DoctrineMongoDBBundle,malarzm/DoctrineMongoDBBundle,Soullivaneuh/DoctrineMongoDBBundle,jahller/DoctrineMongoDBBundle