Update API v4 cdn_locks documentation to include currently missing response structure

[Kasambx]

the following pull request provides some context for the deletion request of the API v4

---

Which Traffic Control components are affected by this PR?

• Documentation

PR submission checklist

• [ ] This PR has tests
• [ ] This PR has documentation
• [ ] This PR has a CHANGELOG.md entry
• [ ] This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

[mitchell852]

@Kasambx - are you able to make the requested change?

[ocket8888]

After a full year without activity, I'm closing this.