Make table in example less wide.

doc/src/sgml/ref/show.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/show.sgml,v 1.49 2010/04/03 07:23:02 petere Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/show.sgml,v 1.50 2010/05/17 20:50:44 alvherre Exp $
 PostgreSQL documentation
 -->
 
@@ -168,14 +168,14 @@ SHOW geqo;
    Show all settings:
 <programlisting>
 SHOW ALL;
-              name               |                     setting                     |                                                          description                                                          
----------------------------------+-------------------------------------------------+-------------------------------------------------------------------------------------------------------------------------------
- allow_system_table_mods         | off                                             | Allows modifications of the structure of system tables.
+            name         | setting |                description                                                          
+-------------------------+---------+-------------------------------------------------
+ allow_system_table_mods | off     | Allows modifications of the structure of ...
     .
     .
     .
- xmloption                       | content                                         | Sets whether XML data in implicit parsing and serialization operations is to be considered as documents or content fragments.
- zero_damaged_pages              | off                                             | Continues processing past damaged page headers.
+ xmloption               | content | Sets whether XML data in implicit parsing ...
+ zero_damaged_pages      | off     | Continues processing past damaged page headers.
 (196 rows)
 </programlisting>
   </para>