add / after .. + tab

zshrc

 zstyle ':completion:*' use-compctl false
 zstyle ':completion:*' verbose true
 zstyle ':completion:*:kill:*' command 'ps -u $USER -o pid,%cpu,tty,cputime,cmd'
+zstyle ':completion:*' special-dirs true
 
 # History configurations
 HISTFILE=~/.zsh_history