Changed how the mktemp trick work.

This way actually has a couple of advantages.

1. With this you write something like $ _ vim file.xml. This is
automatically drop you into a tmp dir then run the vim command.
2. zsh completions aren't still work.

zsh/modules/alias/init.zsh

@@ -15,7 +15,7 @@ alias docker="sudo docker"
 alias dc="sudo docker-compose"
 
 # Goes to a temp folder. This will be deleted on restart.
-alias tmp="cd $(mktemp -d)"
+alias _="cd `mktemp -d` ; "
 
 alias :q="exit"