Remove "...assumes you're using Symfony Standard Edition (version 3.3) services.yaml..."

[weaverryan]

Sorry if this is a dup! In service_container.rst on 4.0, we currently have:

The documentation assumes you're using Symfony Standard Edition (version 3.3) services.yaml configuration

Also, the exact way this looks may be different now. See symfony/recipes#285

[weaverryan]

Fixed in #8751