Sync OpenBSD patchset 901:
Sync OpenBSD patchset 901:

Don't use strnvis for the title as it breaks UTF-8. set-titles is now
off by default and we have to trust the terminal can understand what we
send it anyway so there isn't any harm.


klaxalk/tmux,klaxalk/tmux,klaxalk/tmux,klaxalk/tmux,klaxalk/tmux