feat(tmux): use mattn/memo

[mattn/memo](https://github.com/mattn/memo)

dot.tmux.conf

@@ -173,7 +173,7 @@ bind-key / command-prompt "split-window -l 60% 'exec man %%'"
 
 ## quick memo
 unbind-key m
-bind-key m split-window -v -l 40% "$EDITOR ~/tmp/memo.md"
+bind-key m split-window -v -l 40% "memo new"
 
 ## quickly invoke any command
 unbind-key a