Add link and additional index reference to pgcrypto.

Kevin Grittner, with markup adjustments.

doc/src/sgml/pgcrypto.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/pgcrypto.sgml,v 1.11 2010/08/10 20:42:01 petere Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/pgcrypto.sgml,v 1.12 2010/08/15 01:57:03 rhaas Exp $ -->
 
 <sect1 id="pgcrypto">
  <title>pgcrypto</title>
@@ -7,6 +7,11 @@
   <primary>pgcrypto</primary>
  </indexterm>
 
+ <indexterm zone="pgcrypto">
+  <primary>encryption</primary>
+  <secondary>for specific columns</secondary>
+ </indexterm>
+
  <para>
   The <filename>pgcrypto</> module provides cryptographic functions for
   <productname>PostgreSQL</>.

doc/src/sgml/runtime.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.436 2010/05/26 23:49:19 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.437 2010/08/15 01:57:03 rhaas Exp $ -->
 
 <chapter Id="runtime">
  <title>Server Setup and Operation</title>
@@ -1503,8 +1503,9 @@ $ <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput
    <listitem>
     <para>
      The <filename>contrib</> function library
-     <function>pgcrypto</function> allows certain fields to be stored
-     encrypted. This is useful if only some of the data is sensitive.
+     <link linkend="pgcrypto"><function>pgcrypto</function></link>
+     allows certain fields to be stored encrypted.
+     This is useful if only some of the data is sensitive.
      The client supplies the decryption key and the data is decrypted
      on the server and then sent to the client.
     </para>