yank: add a comment to set allow-passthrough in tmux.conf

[JonathanWheeler]

Not having allow-passthrough on set in .tmux.conf was the cause of yank not working for me. I note that you have this set in your .tmux.conf, but it's not mentioned in this file or on your site. You may want to update your site accordingly.

On a related note, I noticed that the tmux escape sequence doesn't even seem to be necessary. I can alternatively comment out the line test -n "$TMUX" -o -z "${TERM##screen*}" && esc="\033Ptmux;\033$esc\033\\", and everything works fine (including without this configuration change to .tmux.conf) with the following versions I've tested:

macOS 12.4 - 13.3.1: iTerm2 3.4.16 - 3.4.19 OpenSSH 8.6p1 - 9.0p1 tmux 3.3a

Ubuntu 20.04 - 22.04.2: OpenSSH 8.2p1 - 8.9p1 tmux 3.2 - 3.3a

(Specifically when SSH'ing from macOS to Ubuntu, but not the other way around, since GNOME Terminal 3.36.2 on Ubuntu still doesn't support OSC52.)

Unless you're knowingly supporting a (perhaps older?) version of tmux that requires allow-passthrough on, you may want to consider testing whether the Ptmux; escape sequence is still necessary on your end, and if not, simply remove it.

Thanks for sharing your awesome work!

[sunaku]

Excellent! :ok_hand: Great catch, thank you. :pray: I'll adjust the documentation a bit and merge soon. :nerd_face:

[sunaku]

Merged now via cherry-pick (with minor revisions to the verbiage) in commit 67bd04e4587c40691610b8adc7561596c525bcfc. :pray: Thanks for your contribution!