installation premium hook instruction in ARM refer to subscription hook list

Minor thing in: https://kea.readthedocs.io/en/kea-2.1.4/arm/hooks.html#installing-hook-packages point 5 of the list:

5. Rerun configure, using the same configuration options that were used when originally building Kea. It is possible to verify that configure has detected the premium package by inspecting the summary printed when it exits. The first section of the output should look something like this:

Package:
  Name:             kea
  Version:          2.1.4
  Extended version: 2.1.4 (tarball)
  OS Family:        Linux
  Using GNU sed:    yes
  Premium package:  yes
  Included Hooks:   forensic_log flex_id host_cmds subnet_cmds radius host_cache class_cmds cb_cmds lease_query

included hooks list if from subscribes package, may lead to questions like "I bought hooks and according to docs I should have more".