The top blocks 'primaries' and 'parental-agents' are no longer preferred and should be renamed to 'remote-servers'. The zone statements 'parental-agents' and 'primaries' are still used, and may refer to any 'remote-servers' top block.
Closes #4544
Backport of MR !9822
Merge branch 'backport-4544-primaries-block-documentation-issues-9.20' into 'bind-9.20'
See merge request isc-projects/bind9!9911