pwd.1: update /home in example

[• karels]

Summary

The default location for home directories is moving from /usr/home
to /home, and the /home symlink will no longer exist. Switch to
another example that is in base, /sys.

[fernape]

LGTM.

Note: this will need a bump of .Dd at commit time.

Thanks!

[• karels]

Closed by commit rG108230743472: pwd.1: replace /home with /sys in example (authored by karels).