vt: Add devctl message for bells

[imp]

Summary

Generate VT events when the bell beeps. When coupled with disabling the
bell,this allows custom bells to be rung when we'd otherwise beep.

[kevans]

sbin/devd/devd.conf.5

608

share/man/man4/vt.4

304

sys/dev/vt/vt_core.c

1122

Maybe pedantic, but I think this should capture (vd->vd_flags & VDF_QUIET_BELL) != 0 as well -- it's not specified in the manpage update whether enabled=false is purely user-driven or if it'll also be set if the console driver's disabled the bell, but I suspect it should cover console-disabled as well.

it'd probably be good to juts add a bell_enabled bool above that captures the below two cases, so you can just reuse it here and with one return below.

[• hselasky]

Looks good! Waiting for a reply on @kevans comments.

[imp]

updates in a minute

sys/dev/vt/vt_core.c

1122

I'll go for 'hushed' but I like it.

[imp]

update per review comments

[kevans]

sys/dev/vt/vt_core.c

1122

perfect, thanks