Document netstat -Q flags meaning.

MFC after:	1 week
Fixup r248032:
Change size requested to malloc(9) now that callwheel buckets are
callout_list and not callout_tailq anymore. This change was already
there but it seems it got lost after code churn in r248032.

Reported by:	alc, kib
Add forgotten .El

MFC with:	r248112