Re-add documentation for --no-readline option of psql, mistakenly removed a...

Re-add documentation for --no-readline option of psql, mistakenly removed a decade ago. Backpatch to release 7.4.

doc/src/sgml/ref/psql-ref.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/psql-ref.sgml,v 1.227 2009/07/25 17:04:19 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/psql-ref.sgml,v 1.228 2009/08/10 02:39:04 adunstan Exp $
 PostgreSQL documentation
 -->
 
@@ -240,6 +240,17 @@ PostgreSQL documentation
       </listitem>
     </varlistentry>
 
+	<varlistentry>
+      <term><option>-n</></term>
+      <term><option>--no-readline</></term>
+      <listitem>
+      <para>
+       Do not use readline for line editing and do not use the history.
+       This can be useful to turn off tab expansion when cutting and pasting.
+      </para>
+      </listitem>
+    </varlistentry>
+
     <varlistentry>
       <term><option>-o <replaceable class="parameter">filename</replaceable></></term>
       <term><option>--output <replaceable class="parameter">filename</replaceable></></term>