[gtk] Add GtkNative to the docs

[Matthias Clasen <matthiasc src gnome org>]

commit 353df67c0b0639a908cf0d2ad8b048b1c6e90b7e
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Dec 12 18:21:16 2019 -0500

    Add GtkNative to the docs
    
    It was not included in the generated docs.

 docs/reference/gtk/gtk4-docs.xml | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/docs/reference/gtk/gtk4-docs.xml b/docs/reference/gtk/gtk4-docs.xml
index 271b68153e..8d4a96f66d 100644
--- a/docs/reference/gtk/gtk4-docs.xml
+++ b/docs/reference/gtk/gtk4-docs.xml
@@ -72,6 +72,7 @@
     <chapter id="WindowWidgets">
       <title>Windows</title>
       <xi:include href="xml/gtkroot.xml" />
+      <xi:include href="xml/gtknative.xml" />
       <xi:include href="xml/gtkwindow.xml" />
       <xi:include href="xml/gtkdialog.xml" />
       <xi:include href="xml/gtkmessagedialog.xml" />