[docs] Reorganize structs into chapters

Instead of displaying all structures and methods
in girepository.h on one page, split them out to a
bunch of pages.

docs/reference/gi-docs.sgml

@@ -31,11 +31,39 @@ Bla bla bla bla bla
   </chapter>
 -->
 
-  <chapter id="gi-repository">
-    <title>GIRepository</title>
-    <xi:include href="xml/girepository.xml"/>
-    <xi:include href="xml/girffi.xml"/>
-  </chapter>
+  <part id="girepository">
+    <chapter id="gi-libgirepository">
+      <title>GIRepository</title>
+      <xi:include href="xml/girepository.xml"/>
+    </chapter>
+    <chapter id="gi-ffi">
+      <title>GIR Foreign functions interface</title>
+      <xi:include href="xml/girffi.xml"/>
+    </chapter>
+    <chapter id="gi-repository-structs">
+      <title>GIRepository structs</title>
+      <xi:include href="xml/gibaseinfo.xml"/>
+      <xi:include href="xml/gifunctioninfo.xml"/>
+      <xi:include href="xml/gicallableinfo.xml"/>
+      <xi:include href="xml/giarginfo.xml"/>
+      <xi:include href="xml/gitypeinfo.xml"/>
+      <xi:include href="xml/gistructinfo.xml"/>
+      <xi:include href="xml/giunioninfo.xml"/>
+      <xi:include href="xml/gifieldinfo.xml"/>
+      <xi:include href="xml/gipropertyinfo.xml"/>
+      <xi:include href="xml/givfuncinfo.xml"/>
+      <xi:include href="xml/gisignalinfo.xml"/>
+      <xi:include href="xml/gienuminfo.xml"/>
+      <xi:include href="xml/giregisteredtypeinfo.xml"/>
+      <xi:include href="xml/giobjectinfo.xml"/>
+      <xi:include href="xml/giinterfaceinfo.xml"/>
+      <xi:include href="xml/giconstantinfo.xml"/>
+      <xi:include href="xml/gifunctioninfo.xml"/>
+      <xi:include href="xml/gierrordomaininfo.xml"/>
+    </chapter>
+
+  </part>
+
 
   <part id="gi-gir">
     <title>GIR markup format</title>