Update to FreeBSD handbook: advanced networking chapter

[freebsd_ny-central.org]

Summary

Suggested additional notice on UP-ing a parent network interface when creating VLANs in rc.conf.
See PR 270942.

In case I should keep such brief changes on Bugzilla, please let me know. Thanks!

[leres]

(I don't know how to render the handbook but) the text in this change solves my concerns.

[jrm]

Looks good. I'll commit with this log message unless there are objections.

Author: Chris Moerz <[e-mail]>
Date:   2024-02-22 13:24

    Handbook/Advanced Networking: Add note about VLAN creation

    When adding a new VLAN in rc.conf, the parent interface must be up.  Add
    a note to remind readers of this.

    PR:             270942
    Reviewed by:    jrm, leres
    Differential Revision:  https://reviews.freebsd.org/D43993

[jrm]

documentation/content/en/books/handbook/advanced-networking/_index.adoc

2408–2419

Would it be helpful to add a similar note here?

[freebsd_ny-central.org]

documentation/content/en/books/handbook/advanced-networking/_index.adoc

2408–2419

Good point! I'll add this and update the patch. Thanks!

[freebsd_ny-central.org]

Added command line example for minimum configuration on VLANs.