vimrc: complete longest _and_ show list

vimrc

@@ -10,7 +10,7 @@ set sidescroll=1
 set sidescrolloff=10
 set tabstop=4
 set shiftwidth=4
-set wildmode=longest,list
+set wildmode=longest:list
 set background=dark
 set spelllang=en_us
 set foldminlines=2