Use `autocmd` instead of `au`
Using the short form seemed ironic, since it came just before the section
warning against using short forms.
    
        | author | 
        Chip Hogg <charles.r.hogg@gmail.com> | 
    
    
        | date | 
        Sun, 26 Aug 2012 20:03:48 -0400 | 
    
    
    
        | parents | 
        ac0cc7bd738f 
 | 
    
    
        | children | 
        d6110e1c1451
 | 
    
    
        | branches/tags | 
        (none) | 
    
    
        | files | 
        chapters/18.markdown  | 
    
Changes
    
--- a/chapters/18.markdown	Sun Aug 26 19:58:56 2012 -0400
+++ b/chapters/18.markdown	Sun Aug 26 20:03:48 2012 -0400
@@ -58,8 +58,8 @@
     :::vim
     " Vimscript file settings ---------------------- {{{
     augroup filetype_vim
-        au!
-        au FileType vim setlocal foldmethod=marker
+        autocmd!
+        autocmd FileType vim setlocal foldmethod=marker
     augroup END
     " }}}