Update newer XDG_CONFIG/tmux.conf to be like ~/.tmux.conf

I should eventually remove the older ~/.tmux.conf, but until all my
systems are on the latest tmux I have to sync like this.

private_dot_config/tmux/tmux.conf

@@ -1,3 +1,5 @@
+set-option -g default-shell /usr/bin/fish
+
 bind-key h select-pane -L
 bind-key j select-pane -D
 bind-key k select-pane -U
@@ -10,9 +12,10 @@ bind-key a send-prefix
 set -g escape-time 0
 set -g renumber-windows on
 
-# bind Ctrl-k to clearing history
-bind-key c clear-history
-
 # Show a visual bell, even on other windows
 set-window-option -g visual-bell both
 set-window-option -g bell-action other
+
+# Set up the window visuals
+set -g window-status-style bg=yellow
+set -g window-status-current-style bg=red,fg=white