pgsql: Explain automatic creation (or lack of it) of indexes for the

Log Message:
-----------
Explain automatic creation (or lack of it) of indexes for the various types
of constraints.

Kevin Grittner

Modified Files:
--------------
pgsql/doc/src/sgml:
ddl.sgml (r1.96 -> r1.97)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ddl.sgml?r1=1.96&r2=1.97)