[gtk] docs: Remove reference to deleted file

[Timm Bäder <baedert src gnome org>]

commit 51268f53d8698c9df08433279cf8cf2255e9cc11
Author: Timm Bäder <mail baedert org>
Date:   Tue Feb 5 15:15:38 2019 +0100

    docs: Remove reference to deleted file

 docs/reference/gtk/gtk4-docs.xml | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/docs/reference/gtk/gtk4-docs.xml b/docs/reference/gtk/gtk4-docs.xml
index 902dc96a06..7c1a4a0247 100644
--- a/docs/reference/gtk/gtk4-docs.xml
+++ b/docs/reference/gtk/gtk4-docs.xml
@@ -89,7 +89,6 @@
       <xi:include href="xml/gtkactionbar.xml" />
       <xi:include href="xml/gtkheaderbar.xml" />
       <xi:include href="xml/gtkoverlay.xml" />
-      <xi:include href="xml/gtkbbox.xml" />
       <xi:include href="xml/gtkpaned.xml" />
       <xi:include href="xml/gtklayout.xml" />
       <xi:include href="xml/gtknotebook.xml" />