[libadwaita] (4 commits) Non-fast-forward update to branch wip/exalm/tab-fixes

[Adrien Plazas <aplazas src gnome org>]

The branch 'wip/exalm/tab-fixes' 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:

  12fb5ac... tab: Use the default flat style for buttons

Commits added to the branch:

  8b17cd5... tab-view: Add tests for the pages model (*)
  7640bfd... tab-view: Update the model later when attaching pages (*)
  2bae1bb... clamp: Fix using "width" instead of "size" in doc (*)
  5a07011... tab: Use the default flat style for buttons

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