[gtk] (41 commits) Non-fast-forward update to branch matthiasc/for-master

[Matthias Clasen <matthiasc src gnome org>]

The branch 'matthiasc/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:

  1752013... popover: Update docs
  fc802df... Documentation fixes
  981191b... introspection: Stop using allow-none

Commits added to the branch:

  12a9a0f... gtkgstmediafile: Remove media-info-updated callback (*)
  7db87a8... Merge branch 'fix-gst-media-file' into 'master' (*)
  c5eb2f5... gdk: annotate Content Serialize/Deserialize return_error (*)
  e9ca8d6... Merge branch 'bilelmoussaoui/gdk-return-error-annotation' i (*)
  0e1d6fb... Update Ukrainian translation (*)
  894adea... Update Ukrainian translation (*)
  fb6c6c8... checkbutton: Don't allow to uncheck radios by activating th (*)
  bff7ac4... popover: Update docs (*)
  430be6f... Merge branch 'popover-docs' into 'master' (*)
  0017b4b... icons: Fix switch-off icon (*)
  94b0907... Merge branch 'wip/exalm/switch-icons-2' into 'master' (*)
  ab6a5be... Fix documentation syntax (*)
  8ba16eb... Documentation fixes (*)
  7fe0610... introspection: Stop using allow-none (*)
  4a0d3d7... docs: Reduce redundancy (*)
  345edb8... Merge branch 'doc-tweaks' into 'master' (*)
  f5bd9f7... Merge branch 'wip/exalm/check-activate' into 'master' (*)
  0996552... demos: Clean up doc comments
  2d0957b... docs: Clean up docs syntax
  fff2b3c... gdk: Clean up docs syntax
  2d266d1... gsk: Clean up docs syntax
  91f7b96... gtk: Clean up docs syntax
  fc9f580... docs: Update GSK_RENDERER docs
  0bba361... docs: Avoid stairstepping
  252edbd... docs: Fix a typo
  b617ba1... docs: Refer to backend APIs
  786e28f... filter: Cosmetic docs changes
  8761048... sorter: Cosmetic docs changes
  9a7e4f4... eventcontroller: Cosmetic docs changes
  2d12a7d... directorylist: Cosmetic docs changes
  6cb4dda... gdk: Cosmetic docs changes
  b35e02d... shortcutscontroller: Cosmetic docs changes
  13a9348... widget: Cosmetic docs changes
  3ab34ff... text: Cosmetic docs fixes
  74a39bb... textview: Cosmetic docs changes
  f5f8f83... textbuffer: Cosmetic docs changes
  09244ed... expression: Cosmetic docs changes
  fe56431... sortlistmodel: Cosmetic docs changes
  601a8de... treemodel: Cosmetic docs changes
  40f292c... docs: Sync up debug flag information
  8bcc6b1... docs: Fix up syntax

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