[affeldt-aist]

Motivation for this change

forgot to empty CHANGELOG_UNRELEASED when releasing 1.19.0

Checklist

• appended entries in the relevant sections of CHANGELOG_UNRELEASED.md

• added corresponding documentation in the headers

Reference: How to document

Merge policy

As a rule of thumb:

• PRs with several commits that make sense individually and that
  all compile are likely to be merged as they are into master.
• PRs with disorganized commits are very likely to be squash-rebased.

Reminder to reviewers

• Read this Checklist
• Put a milestone if possible
• Check labels