[gtk/matthiasc/for-master] (22 commits) ...Drop GtkReliefStyle

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  03080f2... css: use :focus-visible instead of :focus(visible) (*)
  e83d87c... Add :focus-visible to css docs (*)
  86f295f... x11: emit ::enter/leave-monitor (*)
  3cb023d... Merge branch 'monitor-signals-x11' into 'master' (*)
  54b99d2... Add a focus-within state (*)
  5095e87... testsuite: Add some checks for focus states (*)
  4516bfb... Adwaita: Some adjustments for :focus-within (*)
  1d1e1c5... Merge branch 'css-focus-changes' into 'master' (*)
  b3b1945... Merge branch 'matthiasc/for-master' into 'master' (*)
  0d065bc... Fix compiler warning (*)
  5abb6f2... Fix annotation for gtk_show_uri_full() (*)
  96cfb12... Fix annotations for GtkEventController (*)
  f28aa1b... Restructure the GdkEvent type hierarchy (*)
  60329c3... Merge branch 'event-types' into 'master' (*)
  4df75f1... scrolledwindow: Drop shadow-type
  b71bd33... scrolledwindow: Document the .frame style class
  b030188... frame: Drop shadow-type
  30abcf9... viewport: Drop shadow-type
  23d3d6f... Drop GtkShadowType
  b7913cf... button: Drop relief
  dc8e7be... menubutton: Drop relief
  1859551... Drop GtkReliefStyle

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