[libadwaita] (3 commits) Non-fast-forward update to branch wip/cdavis/header-suffix

[Alexander Mikhaylenko <alexm src gnome org>]

The branch 'wip/cdavis/header-suffix' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  bcf74f7... preferences-group: Add support for a header suffix
  d711665... doc: Add suffix to preferences group images

Commits added to the branch:

  6605543... demo: Remove Frobnicate (*)
  eef3fee... preferences-group: Add support for a header suffix
  ae9458d... doc: Add suffix to preferences group images

(*) This commit already existed in another branch; no separate mail sent