Improve pg_restore docs

Hi,

 From a quick discussion on hackers
(http://archives.postgresql.org/pgsql-hackers/2009-06/msg01434.php), it
appears the documentation can improve for pg_restore.

I've prepared some quick diff output from
pgsql/doc/src/sgml/ref/pg_restore.sgml for some changes that I think
would help. Note that I'm not entirely sure about the default namespace
from default_path .. please verify this before accepting. Edit as necessary.

291c291,292
<         specific table.
---
 >         specific table.  The default is taken from the
 >         <envar>default_path</envar> variable.
379c380,382
<         Restore definition and/or data of named table only.
---
 >         Restore definition and/or data of named table only. This can be
 >         combined with the <option>-n</option> option to restore a table
 >         from a specific schema.


Thanks,

-Mike