do not correct tree command

.zsh/lib/correction.zsh

 setopt correct_all
 
 alias man='nocorrect man'
+alias tree='nocorrect tree'
 alias thor='nocorrect thor'
 alias mv='nocorrect mv'
 alias mysql='nocorrect mysql'
@@ -8,4 +9,5 @@ alias mkdir='nocorrect mkdir'
 alias gist='nocorrect gist'
 alias heroku='nocorrect heroku'
 alias ebuild='nocorrect ebuild'
-alias hpodder='nocorrect hpodder'
\ No newline at end of file
+alias hpodder='nocorrect hpodder'
+