Match Tmux's "o" behavior in default keybinds

[ArcticLight]

Hello!

This is a very-minor fix to the default keybinds to mirror that Tmux goes back to Normal mode after Ctrl-B o by default. It's fine if you do not want to accept this, but this is how Tmux behaves for this bind (at least as of 3.4 which is on my systems, but I believe since much earlier). Thank you so much for making such a quality piece of software, and I really appreciate the inclusion of Tmux keybindings, as it's helping me transition to Zellij without relearning all my muscle-memory!

Thank you so much, Arctic.