[gtk] (32 commits) Non-fast-forward update to branch ci-style

[Emmanuele Bassi <ebassi src gnome org>]

The branch 'ci-style' 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:

  ae400fd... ci: Create new origin for forks

Commits added to the branch:

  8a269de... multiselection: Update docs (*)
  674ede8... docs: Remove ancient version information (*)
  6a4b5ea... Annotate nullable argument (*)
  24d6a19... Add pre-condition check on nullable argument (*)
  117c71f... Merge branch 'issue-2900' into 'master' (*)
  608cbc2... printeditor: Cosmetics (*)
  6774f36... print-editor: Allow opening files (*)
  59fe4a3... printeditor: Add desktop file and appdata (*)
  ddcba4d... bitset: Cosmetic documentation changes (*)
  7c98af6... stack: Cosmetic documentation fixes (*)
  4d7d031... gdk: Small documentation fixes (*)
  9dff4d6... stack: Remove nonexisting api from headers (*)
  334f954... sorter: Some doc corrections (*)
  7047d68... gtk: Add some missing symbols to the docs (*)
  5d9bcfb... stringlist: Cosmetic documentation fix (*)
  0c9a0df... Merge branch 'print-editor' into 'master' (*)
  6819c7c... docs: Update environment sections (*)
  4fa71fd... shortcuts: Use GTK_DEBUG_KEYBINDINGS (*)
  30eca5a... Drop GTK_DEBUG_SHORTCUTS (*)
  d46b046... wayland: Respect GDK_DEBUG=default-settings (*)
  d31bb8b... testsuite: Don't pass GDK_DEBUG for release builds (*)
  9f2926d... gdk: Better help for GDK_DEBUG (*)
  93a51f7... gsk: Better help for GSK_DEBUG (*)
  a6752bd... gtk: Better help for GTK_DEBUG (*)
  5229069... widget: Avoid uninitialized access (*)
  1f8c79e... Add g_intern_static_string to valgrind suppressions (*)
  01fbf84... Stop setting GTK_IM_MODULE_FILE (*)
  6a6146a... bitset: Fix the right-shift implementation (*)
  3dc6267... testsuite: Bump the per-test timeout to 60s (*)
  3132353... ci: Drop one of the focus tests (*)
  c4b2112... Merge branch 'matthiasc/for-master' into 'master' (*)
  3647427... ci: Create new origin for forks

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