The PID of the logger process is always recorded along with the move from RFC
3164 to RFC 5424.
Indicate the -i flag is a no-op now in logger(1). We could probably remove the
`-i` flag since its presence [[https://pubs.opengroup.org/onlinepubs/9699919799/|does not seem to be enforced]]
but that might cause breakage in user scripts.
Related to a similary change in syslog.3.
Reported by: danfe@