[gtk] docs: Put selection models into a section

[Matthias Clasen <matthiasc src gnome org>]

commit 856c8950ffd5538e59ffa27b843175a17c3b14f0
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Jun 6 13:19:07 2020 -0400

    docs: Put selection models into a section
    
    This makes the documentation structure a bit clearer.

 docs/reference/gtk/gtk4-docs.xml | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/docs/reference/gtk/gtk4-docs.xml b/docs/reference/gtk/gtk4-docs.xml
index b6d09c9335..2f8924b313 100644
--- a/docs/reference/gtk/gtk4-docs.xml
+++ b/docs/reference/gtk/gtk4-docs.xml
@@ -68,10 +68,12 @@
         <xi:include href="xml/gtkmultisorter.xml" />
       </section>
       <xi:include href="xml/gtkselectionmodel.xml" />
-      <xi:include href="xml/gtknoselection.xml" />
-      <xi:include href="xml/gtksingleselection.xml" />
-      <xi:include href="xml/gtkmultiselection.xml" />
+      <section>
+        <xi:include href="xml/gtknoselection.xml" />
+        <xi:include href="xml/gtksingleselection.xml" />
+        <xi:include href="xml/gtkmultiselection.xml" />
       <xi:include href="xml/gtkpropertyselection.xml" />
+      </section>
       <xi:include href="xml/gtkdirectorylist.xml" />
     </chapter>