Small wording correction for Guide chapter 3

Andras Farkas <[email protected]> Wed, 15 Dec 2021 20:26:01 -0800
Newsgroups gmane.os.netbsd.documentation
Message-ID <CAA0nTRszmzedwhdT-uOv270vdMaFcnn2pOqQvSLwaWJ0OydTzA@mail.gmail.com>
https://www.netbsd.org/docs/guide/en/chap-exinst.html#exinst-from-cdrom
optic medium -> optical disc
("optical medium" would also be an improvement over "optic medium",
yet not as good as "optical disc")