[Secrets] Secret management

[ghostika]

I asked this already at the #12958 PR but reading the documentation now on the Symfony page I have to ask it again
Is the YAML implementation under the section Referencing Secrets in Configuration Files correct without the SECRET:?

If yes, then it would be good to explain this in the documentation, why the XML and PHP implementation requires the secret prefix for the secret env var.

[javiereguiluz]

@weaverryan do you know if this is a typo or a difference in the YAML syntax? Thanks!