
911e7020770 added opclass options and adjusted documentation for each particular affected opclass. However, documentation for extendability was not adjusted. This commit adjusts documentation for interfaces of index AMs and opclasses. Discussion: https://postgr.es/m/CAH2-WzmQnW6%2Bz5F9AW%2BSz%2BzEcEvXofTwh_A9J3%3D_WA-FBP0wYg%40mail.gmail.com Author: Alexander Korotkov Reported-by: Peter Geoghegan Reviewed-by: Peter Geoghegan