[gtk] (3 commits) Non-fast-forward update to branch wip/baedert/for-master

[Timm Bäder <baedert src gnome org>]

The branch 'wip/baedert/for-master' 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:

  73ebdcf... fixedlayout: Don't call the child transform position
  3916370... fixed: x/y passed to get_child_position are not optional
  06e8d6b... fixed: Documentation clarifications

Commits added to the branch:

  433c277... fixedlayout: Don't call the child transform position
  83f36d3... fixed: x/y passed to get_child_position are not optional
  5950c63... fixed: Documentation clarifications