Add emacs setup for the docs/devinfo.html comment wrapping recommendation.

Reviewed-by: Brian Paul <brianp@vmware.com>
diff --git a/.dir-locals.el b/.dir-locals.el
index 3bd8328..4f0ad7a 100644
--- a/.dir-locals.el
+++ b/.dir-locals.el
@@ -3,6 +3,7 @@
   (tab-width . 8)
   (c-basic-offset . 3)
   (c-file-style . "stroustrup")
+  (fill-column . 78)
   (eval . (progn
 	    (c-set-offset 'innamespace '0)
 	    (c-set-offset 'inline-open '0)))