Remove $FreeBSD$: two-line nroff pattern

Remove /^\.\\"\n\.\\"\s*\$FreeBSD\$$\n/

efitable(8): Add missing `-u` in the manpage

PR: 261524
MFC after: 3 days

Add efitable(8), a userspace tool to fetch and parse EFI tables

Only ESRT and PROP tables are handled at the moment.

Submitted by: Pavel Balaev <pavel.balaev@3mdeb.com>
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D30104