Status reports: Improve call for reports email

Specify that if the directory where it is asked to put status reports
does not exist yet, then it should be created, as it is already done in
https://docs.freebsd.org/en/articles/freebsd-status-report-process/#_submit_your_report

PR: 269892
Reported by: grahamperrin
Approved by: debdrup (status blanket)