docs: add preview to fzf example (#16)

Author: danitrap

README.md

@@ -111,7 +111,7 @@ In order to integrate with tmux, you can add a binding to your tmux config (`tmu
 
 ```sh
 bind-key "T" run-shell "sesh connect \"$(
-  sesh list --icons | fzf-tmux -p 55%,60% \
+  sesh list --icons | fzf-tmux -p 80%,70% \
     --no-sort --ansi --border-label ' sesh ' --prompt '⚡  ' \
     --header '  ^a all ^t tmux ^g configs ^x zoxide ^d tmux kill ^f find' \
     --bind 'tab:down,btab:up' \
@@ -121,6 +121,8 @@ bind-key "T" run-shell "sesh connect \"$(
     --bind 'ctrl-x:change-prompt(📁  )+reload(sesh list -z --icons)' \
     --bind 'ctrl-f:change-prompt(🔎  )+reload(fd -H -d 2 -t d -E .Trash . ~)' \
     --bind 'ctrl-d:execute(tmux kill-session -t {2..})+change-prompt(⚡  )+reload(sesh list --icons)' \
+    --preview-window 'right:55%' \
+    --preview 'sesh preview {}'
 )\""
 ```