[rygel] docs: Finish a sentence.

[Murray Cumming <murrayc src gnome org>]

commit 70b6fadd5bd7dadb9e472a9cbaf283a52c4faa35
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Jan 17 12:51:10 2013 +0100

    docs: Finish a sentence.

 .../gtkdoc/implementing-server-plugins.xml         |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/doc/reference/librygel-server/gtkdoc/implementing-server-plugins.xml b/doc/reference/librygel-server/gtkdoc/implementing-server-plugins.xml
index 786b1f4..bd90bc3 100644
--- a/doc/reference/librygel-server/gtkdoc/implementing-server-plugins.xml
+++ b/doc/reference/librygel-server/gtkdoc/implementing-server-plugins.xml
@@ -82,7 +82,8 @@ implemented in Vala.
 
 <para>The <classname>RygelMediaExportPlugin</classname> class, derived from <link linkend="RygelMediaServerPlugin">RygelMediaServerPlugin</link>, simply instantiates its <classname>RygelMediaExportRootContainer</classname> class, derived from <link linkend="RygelMediaContainer">RygelMediaContainer</link>, providing it to the base class as the root container.</para>
 
-<para>TODO: Describe the <classname>RygelMediaExportRootContainer</classname> class.</para>
+<para>The <classname>RygelMediaExportRootContainer</classname> creates an instance of its RygelMediaExportMediaCache, which uses SQLite to maintain a cache of the media files that it finds on the file system.</para>
+<!-- TODO: Simplify the class hierarchy in the example. -->
 
 </section>