sdk-manual: Minor intro wording change

(From yocto-docs rev: 953db3d0b5fe14411e944b021a2f6f50a5bdeabd)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/sdk-manual/sdk-appendix-customizing.xml

@@ -7,7 +7,7 @@
 <title>Customizing the Extensible SDK</title>
 
 <para>
-    This appendix presents customizations you can apply to the extensible SDK.
+    This appendix describes customizations you can apply to the extensible SDK.
 </para>
 
 <section id='sdk-configuring-the-extensible-sdk'>