Replace refs to v6.6 with v7.0.

doc/src/sgml/xfunc.sgml

@@ -983,7 +983,7 @@ memmove(destination->data, buffer, 40);
     <title>Name Space Conflicts</title>
 
     <para>
-     As of <productname>Postgres</productname> v6.6, the alternative
+     As of <productname>Postgres</productname> v7.0, the alternative
      form of the AS clause for the SQL
      <command>CREATE FUNCTION</command> command
      decouples the SQL function name from the function name in the C
@@ -992,7 +992,7 @@ memmove(destination-&gt;data, buffer, 40);
     </para>
 
     <sect3>
-     <title>Pre-v6.6</title>
+     <title>Pre-v7.0</title>
 
      <para>
       For functions written in C, the SQL name declared in