[gtk] (9 commits) ...Merge branch 'modern-doc-shooter' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  1e3df88... docs: Redo the doc shooter code (*)
  1d1e1a0... docs: Regenerate widget gallery images (*)
  0ae4604... docs: Add gallery images for some more widgets (*)
  1492e8c... docs: Improve the gallery image for scales (*)
  92cb629... docs: Avoid focus in gallery images (*)
  d7cd28c... docs: Add gallery image for GtkPasswordEntry (*)
  2c306f7... docs: Add a gallery image for GtkEditableLabel (*)
  f49d267... docs: Add a gallery image for GtkDropDown (*)
  b3a874c... Merge branch 'modern-doc-shooter' into 'master'

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