Document new features from symfony/symfony#4937

[Burgov]

symfony/symfony#4937 adds some options to the container:debug command to debug tags. This should be documented.

I'd create a PR, but I'm not really sure what the best place for this is, as the core bundles don't have their own articles... Can anyone point me in the right direction?

[fabpot]

Actually, I think this is not needed as the documentation is already contained in the command itself. Let's close it.