[libadwaita] (7 commits) Non-fast-forward update to branch wip/exalm/dark

[Alexander Mikhaylenko <alexm src gnome org>]

The branch 'wip/exalm/dark' 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:

  70c29ac... Add AdwStyleManager
  83effd9... application: Add style-manager property
  cbc700c... application: Remove gtk-application-prefer-dark-theme menti
  87b6119... application: Use AdwStyleManager properties to control styl
  d7117c4... demo: Rework the dark mode button
  18712cb... doc: Mention HdyStyleManager in migration guide
  1391620... doc: Mention default color scheme change in migration guide

Commits added to the branch:

  e5d55a5... Add AdwStyleManager
  c431392... application: Add style-manager property
  8c3e6bb... application: Remove gtk-application-prefer-dark-theme menti
  3f639b6... application: Use AdwStyleManager properties to control styl
  2a813b0... demo: Rework the dark mode button
  b0c8c7d... doc: Mention HdyStyleManager in migration guide
  054834d... doc: Mention default color scheme change in migration guide