Development utility: kills all panes identified by their tmux pane IDs.
Uses kill-pane -t <pane-id>; panes already gone are ignored. See tmux manual. 1
tmuxKillPanes(panes)Character vector of tmux pane IDs (e.g., c("%2", "%3")) returned by
experimentTmux().
Invisibly returns the subset of panes successfully targeted.