Add XZ Utilities to the rationale page

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@9436 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

prologue/why.xml

@@ -446,6 +446,14 @@
         many users and any other editor could be substituted if desired.</para>
       </listitem>
 
+      <listitem>
+        <para>XZ Utils</para>
+
+        <para>This package contains programs for compressing and decompressing 
+        files.  It provides the highest compression generally available
+        and the useful for decompressing packages XZ or LZMA format.</para>
+      </listitem>
+
       <listitem>
         <para>Zlib</para>