tmux: Keep tmux 2.9 swap-window behaviour
tmux: Keep tmux 2.9 swap-window behaviour

tmux 3.0 changed it so that swapping kept the current index selected,
rather than following the current window to its new index.

https://github.com/5H3LL3H5/tmux/pull/69/commits/39c55d5b6fcafd9476528ebc1064192c90f559a4

jsok/dotfiles,jsok/dotfiles