ref-manual: Addedt gtext class.

(From yocto-docs rev: ca8fd78455c583799509eb2447bc3fbadd91517d)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/ref-classes.xml

@@ -621,6 +621,18 @@
     </para>
 </section>
 
+<section id='ref-classes-gtext'>
+    <title><filename>gtext.bbclass</filename></title>
+
+    <para>
+        The GText (<filename>gtext</filename>) class provides support for
+        building software that uses the GNU <filename>gettext</filename>
+        internationalization and localization system.
+        All recipes building software that use
+        <filename>gettext</filename> should inherit this class.
+    </para>
+</section>
+
 <section id='ref-classes-pkgconfig'>
     <title>Pkg-config - <filename>pkgconfig.bbclass</filename></title>