* bug: illustrate negative durations don't add to the same time

* fix: equivalent negative durations add to the same time

Co-authored-by: Caleb <me@cpb.ca>
Co-authored-by: Braden Staudacher <braden.staudacher@chime.com>

* Updates CHANGELOG with fix to `ActiveSupport::Duration.build`

Co-authored-by: Rafael Mendonça França <rafael@rubyonrails.org>