[libadwaita] (7 commits) Non-fast-forward update to branch ebassi/toast-format

[Alexander Mikhaylenko <alexm src gnome org>]

The branch 'ebassi/toast-format' 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:

  4459dba... toast: Add convenience format constructor
  5a76d00... tests: Add unit for adw_toast_new_format()
  f3a25f1... Do not overinclude headers in AdwToast
  881242b... demo: Use adw_toast_new_format() in the toasts demo

Commits added to the branch:

  d5e4e55... toast: Add custom-title property (*)
  36c7b29... preferences-row: correct Since annotation (*)
  447e362... preferences-group: Correct nullable annotation (*)
  59554a7... toast: Add convenience format constructor
  26dc99c... tests: Add unit for adw_toast_new_format()
  f485959... Do not overinclude headers in AdwToast
  db10a8a... demo: Use adw_toast_new_format() in the toasts demo

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