[doc] Add coding style to CONTRIBUTING. (#1640)
[doc] Add coding style to CONTRIBUTING. (#1640)

As suggested by @rgrinberg.

Signed-off-by: Emilio Jesus Gallego Arias <a1debd7f3d9036292773dd21463eb601946b38d8@x80.org>
janestreet/jbuilder,janestreet/jbuilder,dra27/jbuilder,dra27/jbuilder,dra27/jbuilder,dra27/jbuilder,dra27/jbuilder,janestreet/jbuilder,janestreet/jbuilder,janestreet/jbuilder,dra27/jbuilder,janestreet/jbuilder