[gtk] (18 commits) Non-fast-forward update to branch wip/matthiasc/popup

[Matthias Clasen <matthiasc src gnome org>]

The branch 'wip/matthiasc/popup' 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:

  af468fb... wip: introduce GtkPopup
  d4b9a04... testpopup: Use a GtkPopup
  4d3529d... wip: Window assumption in idle sizer
  cdc8967... widget: add popups to not-visible list

Commits added to the branch:

  9861887... inspector: Avoid grabs for inspecting (*)
  c35554c... Drop GtkInvisible (*)
  edc4f95... Revert "inspector: Make picking work again" (*)
  8a0182e... docs: Some cosmetic fixups (*)
  eb1310e... docs: Remove a mention of Gtkinvisible (*)
  eddc823... gitlab templates: Its just GTK now (*)
  d773bc0... docs: Its just GTK now (*)
  fd667bb... docs: Its just GTK now (*)
  77c0e68... gdk: Rename our vulkan context to GTK (*)
  6687a08... Update POTFILES.in (*)
  397b8ee... docs: Its just GTK now (*)
  df27cb7... docs: Remove some no-longer-existing api (*)
  d3c45cb... docs: Miscellaneous doc fixes (*)
  179415c... wip: introduce GtkPopup
  63a32ad... testpopup: Use a GtkPopup
  45466b9... wip: Window assumption in idle sizer
  5bbeba3... widget: Check rootness for invisibility
  43b4c24... Avoid a crash

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