[gtk] Fix the gdk doc build

[Matthias Clasen <matthiasc src gnome org>]

commit 5e2103f7f0a8a15fff82f890996559e4ce6d0580
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Apr 27 20:14:03 2018 -0400

    Fix the gdk doc build
    
    GdkDrawingContext no longer exists.

 docs/reference/gdk/gdk4.types | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/docs/reference/gdk/gdk4.types b/docs/reference/gdk/gdk4.types
index 1aba9be875..e8273d8a3d 100644
--- a/docs/reference/gdk/gdk4.types
+++ b/docs/reference/gdk/gdk4.types
@@ -5,7 +5,6 @@ gdk_device_pad_get_type
 gdk_display_get_type
 gdk_display_manager_get_type
 gdk_drag_context_get_type
-gdk_drawing_context_get_type
 gdk_frame_clock_get_type
 gdk_gl_context_get_type
 gdk_keymap_get_type