Clarify that #includedir isn't a comment
Clarify that #includedir isn't a comment

Added a comment to the `/etc/sudoers` template to explain that `#includedir` is *not* a comment, but an actual directive.
opscode-cookbooks/sudo,juliandunn/sudo,cringdahl/sudo,opscode-cookbooks/sudo,itwasntandy/sudo,chef-cookbooks/sudo,bcg62/sudo,bcg62/sudo,chef-cookbooks/sudo,opscode-cookbooks/sudo,cringdahl/sudo,itwasntandy/sudo,spheromak/sudo,autarchprinceps/sudo,itwasntandy/sudo,spheromak/sudo,spheromak/sudo,juliandunn/sudo,autarchprinceps/sudo