kern/60192: consider mentioning GPT partition tables in handbook installation and cgd chapters

["falsifian%falsifian.org@localhost via gnats" <gnats-admin%NetBSD.org@localhost>]

>Number:         60192
>Category:       kern
>Synopsis:       consider mentioning GPT partition tables in handbook installation and cgd chapters
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          doc-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Apr 15 22:50:00 +0000 2026
>Originator:     James Cook
>Release:        current handbook
>Organization:
>Environment:
NetBSD ucl.h.falsifian.org 10.1 NetBSD 10.1 (GENERIC) #0: Mon Dec 16 13:08:11 UTC 2024  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
The example installation and cryptographic device driver sections of the handbook could benefit from some mention of gpt partition tables.

Mostly I'm filing this to note two things in particular that gave me a bit of trouble:

1. When I first started using NetBSD, I was confused about whether or not I was supposed to still use a disklabel when my disk has a GPT partition table. Mentioning it in the installation section might help. Or maybe in gpt(8) and/or disklabel(8); the latter currently only mentions the distinction under BUGS. (I'm coming from OpenBSD where for better or for worse a disklabel is always used, which is partly why I got confused.)

2. I recently configured an encrypted volume. Mostly I was able to adapt the instructions at https://netbsd.org/docs/guide/en/chap-cgd.html without trouble, but it took me a while to figure out how to work around the possible instability in dk numbering. It turns out I can name my config file /etc/cgd/anything_i_want and then use NAME= syntax in /etc/cgd/cgd.conf. Easy enough to discover in the cgd.conf man page, but it could be streamlined.
>How-To-Repeat:

>Fix: