adjust class_regex

follow up of #1677



if we want to explicitly list cases, we should add more Doctrine\ options:

*    Doctrine\Orm
*    Doctrine\MongoDB
*    Doctrine\CouchDB

see http://symfony.com/doc/current/cookbook/doctrine/mapping_model_classes.html and for a concrete example https://github.com/FriendsOfSymfony/FOSUserBundle/tree/master/Doctrine

i guess that was the reason why @dantleech made this a generic match everything. but i see that breaks another feature. adding the other Doctrine... cases should cover at least the rest of the standard situations.