Fix for texinfo-5.1

=== modified file 'docs/grub-dev.texi'
--- docs/grub-dev.texi	2012-05-22 07:15:28 +0000
+++ docs/grub-dev.texi	2013-04-08 13:23:07 +0000
@@ -1394,8 +1394,8 @@
 
 @node Bitmap API
 @section Bitmap API
-@itemize
 @subsection grub_video_bitmap_create
+@itemize
 @item Prototype:
 @example
 grub_err_t grub_video_bitmap_create (struct grub_video_bitmap **bitmap, unsigned int width, unsigned int height, enum grub_video_blit_format blit_format)