Fix pg_restore -l with the directory archive to display the correct format name.

Back-patch to 9.1 where the directory archive was introduced.
Fix docs on lock level for ALTER TABLE VALIDATE

ALTER TABLE .. VALIDATE CONSTRAINT previously
gave incorrect details about lock levels and
therefore incomplete reasons to use the option.

Initial bug report and fix from Marko Tiikkaja
Reworded by me to include comments by Kevin Grittner
Update CREATE FUNCTION documentation about argument names

More languages than PL/pgSQL actually support parameter names.