Remove references to removed gtk_item_select api
docs: add Gtk*Class docs

https://bugzilla.gnome.org/show_bug.cgi?id=81006
docs: put GtkWindow above subclasses
docs: add missing overrides for QUARTZ and WAYLAND
docs: add missing docs for GDK_WINDOWING_WAYLAND
docs: add missing docs for GDK_DISABLE_DEPRECATION_WARNINGS
wayland: fix rename of wl_shell to xdg_shell

Regression from 9127087e1c0e93f94552f0ad5170d4dfa785146a
docs: add docs for GtkTargetPair
Updated Galician translations
Updated Galician translations
docs: add missing docs for GDK_MODIFIER_RESERVED_*_MASK
docs: add missing GdkEvent field names
docs: add missing scroll delta fields
docs: fix typo in GDK_WINDOW_STATE_TILED
docs: fix docs for GDK_XID_TO_POINTER and GDK_POINTER_TO_XID
docs: add docs for GtkFrameClock
docs: remove link to missing example

Removed in e95490c15e8a95cb72601e4d66e806b55d7b4d82 etc.
docs: fix type in parameter type
docs: fix typo in type name
docs: fix typo in type name