manual nitpick: document sha512 support in hashString

Author: vcunat

doc/manual/expressions/builtins.xml

@@ -693,8 +693,8 @@ builtins.genList (x: x * x) 5
     <listitem><para>Return a base-16 representation of the
     cryptographic hash of string <replaceable>s</replaceable>.  The
     hash algorithm specified by <replaceable>type</replaceable> must
-    be one of <literal>"md5"</literal>, <literal>"sha1"</literal> or
-    <literal>"sha256"</literal>.</para></listitem>
+    be one of <literal>"md5"</literal>, <literal>"sha1"</literal>,
+    <literal>"sha256"</literal> or <literal>"sha512"</literal>.</para></listitem>
 
   </varlistentry>