doc: fix manpage warning
This fixes mdoc warning: Empty input line #389 (closed) that can be seen by doing
LC_ALL=C.UTF-8 MANROFFSEQ='' MANWIDTH=80 man --warnings -E UTF-8 -l -Tutf8 -Z ./doc/node.1 > /dev/null
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This fixes mdoc warning: Empty input line #389 (closed) that can be seen by doing
LC_ALL=C.UTF-8 MANROFFSEQ='' MANWIDTH=80 man --warnings -E UTF-8 -l -Tutf8 -Z ./doc/node.1 > /dev/null