[appendices] Recover ISP's english interpretion

appendices/acronymlist.xml

@@ -321,6 +321,7 @@
     <varlistentry>
       <term><emphasis role="bold">ISP</emphasis></term>
       <listitem>
+        <para>Internet Service Provider</para>
         <para>互联网服务提供者</para>
       </listitem>
     </varlistentry>