chat.tmux.conf: Make window selection hotkeys match window numbers

The 'pick chat network' binding on F1 lists tmux windows as follows
and tmux's `choose-tree -Z' lets you jump to the window by pressing the
key denoted inside parantheses.

Set `base-index 1' so as to make window indices match up the hotkey
number instead of being off-by-one due to the session itself being the
first entry in the list.

  (0)   - chat-5: 8 windows (group chat: chat-0,chat-1,chat-2,chat-3,chat-4,chat-5,chat-6) (attached)
  (1)   ├─>   1: hackint: "example.com"
  (2)   ├─>   2: efnet: "example.com"
  ...

PS: Update existing sessions by updating chat.tmux.conf, pressing F5
then running `prefix-: move-window -r' to renumber all windows.

scripts/chat.tmux.conf

@@ -20,6 +20,9 @@ set-option -g	-- automatic-rename	off
 set-option -g	-- allow-rename	off
 set-option -g	-- set-titles	off
 set-option -g	-- renumber-windows	on
+# for the F1 binding, make hotkeys match window numbers
+set-option -g	-- base-index	on
+
 
 # clients exit on network errors, restart them automatically
 # (use `kill-pane'/`C-b x' to destroy windows)