[gdk-pixbuf] docs: Hide Xlib types

[Emmanuele Bassi <ebassi src gnome org>]

commit 759e316209ee37bf2a2323fcf9ceff287522cb65
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Apr 26 12:02:35 2018 +0100

    docs: Hide Xlib types
    
    We cannot expand those, as Xlib does not come with a gtk-doc index.

 docs/reference/gdk-pixbuf/gdk-pixbuf-sections.txt |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/docs/reference/gdk-pixbuf/gdk-pixbuf-sections.txt 
b/docs/reference/gdk-pixbuf/gdk-pixbuf-sections.txt
index ab57553..b64fa6c 100644
--- a/docs/reference/gdk-pixbuf/gdk-pixbuf-sections.txt
+++ b/docs/reference/gdk-pixbuf/gdk-pixbuf-sections.txt
@@ -419,5 +419,14 @@ xlib_rgb_get_visual_info
 xlib_rgb_get_depth
 xlib_rgb_get_display
 xlib_rgb_get_screen
+<SUBSECTION Private>
+Bool
+Colormap
+Display
+Drawable
+GC
+Pixmap
+Screen
+Visual
 </SECTION>