Re: git: 915af883221a - main - Explain the -d option.

> The branch main has been updated by grog:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=915af883221a4982e89ef878f1def0899ccac283
> ...
>     Explain the -d option.

Not picking on this commit specifically but it's a good opportunity
for a reminder that we have a comprehensive set of guidelines in the
committer's guide:
https://docs.freebsd.org/en/articles/committers-guide/#commit-log-message

We've had some recent commits that don't follow the preferred format
-- overly long lines, missing empty second line, etc.

For this commit the issue is our preferred commit message subject
format starts with a component. That is, for this commit the preferred
commit message would be:

makefs: Explain the -d option

This makes it easy to find commits of interest in short logs, e.g. the
five most recent commits as of now:

$ git log --oneline freebsd/main | head -n 5
915af883221a Explain the -d option.
1d6021cd7268 nvme: Supress noise messages
1117b3204873 pf.4: Bump .Dd
3fb80f1476c7 regcomp: use unsigned char when testing for escapes
61f8df6a13a3 mfc-candidates: search by committer only, not author