pgsql: Clarify documentation that primary key and unique constraints ar

Clarify documentation that primary key and unique constraints are copied
for CREATE TABLE LIKE ... INCLUDING INDEXES.

Per report from david.sahagian@emc.com

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/de87d4704432e98a327dbf42dbc4711fa2628a9c

Modified Files
--------------
doc/src/sgml/ref/create_table.sgml |   17 +++++++----------
1 files changed, 7 insertions(+), 10 deletions(-)