[gtk+] Add an index for 3.22 api additions

[Matthias Clasen <matthiasc src gnome org>]

commit 7e15ac8927ec5b5b89dd1f36e3996dc2af9a62b2
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Mar 26 23:32:45 2016 -0400

    Add an index for 3.22 api additions

 docs/reference/gtk/gtk-docs.sgml |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/docs/reference/gtk/gtk-docs.sgml b/docs/reference/gtk/gtk-docs.sgml
index f290973..d091acf 100644
--- a/docs/reference/gtk/gtk-docs.sgml
+++ b/docs/reference/gtk/gtk-docs.sgml
@@ -488,6 +488,10 @@
     <title>Index of new symbols in 3.20</title>
     <xi:include href="xml/api-index-3.20.xml"><xi:fallback /></xi:include>
   </index>
+  <index id="api-index-3-22" role="3.22">
+    <title>Index of new symbols in 3.22</title>
+    <xi:include href="xml/api-index-3.22.xml"><xi:fallback /></xi:include>
+  </index>
 
   <xi:include href="xml/annotation-glossary.xml"><xi:fallback /></xi:include>