[Docs] use h4 instead h5 headline
[Docs] use h4 instead h5 headline

jordisala1991/SonataAdminBundle,osavchenko/SonataAdminBundle,ARTACK/SonataAdminBundle,greg0ire/SonataAdminBundle,osavchenko/SonataAdminBundle,ARTACK/SonataAdminBundle,peter-gribanov/SonataAdminBundle,Armstrong1992/SonataAdminBundle,jordisala1991/SonataAdminBundle,sonata-project/SonataAdminBundle,greg0ire/SonataAdminBundle,greg0ire/SonataAdminBundle,osavchenko/SonataAdminBundle,peter-gribanov/SonataAdminBundle,osavchenko/SonataAdminBundle,Armstrong1992/SonataAdminBundle,ARTACK/SonataAdminBundle,ARTACK/SonataAdminBundle,jordisala1991/SonataAdminBundle,peter-gribanov/SonataAdminBundle,greg0ire/SonataAdminBundle,osavchenko/SonataAdminBundle,peter-gribanov/SonataAdminBundle,sonata-project/SonataAdminBundle,jordisala1991/SonataAdminBundle