Move information_schema duplicate constraint note to the top of the information schema documentation because it affects several tables.
Move information_schema duplicate constraint note to the top of the
information schema documentation because it affects several tables.

xinzweb/gpdb,jmcatamney/gpdb,50wu/gpdb,snaga/postgres-xl,xinzweb/gpdb,Postgres-XL/Postgres-XL,techdragon/Postgres-XL,Postgres-XL/Postgres-XL,kmjungersen/PostgresXL,ovr/postgres-xl,lisakowen/gpdb,oberstet/postgres-xl,50wu/gpdb,pavanvd/postgres-xl,tpostgres-projects/tPostgres,arcivanov/postgres-xl,snaga/postgres-xl,ashwinstar/gpdb,lisakowen/gpdb,50wu/gpdb,jmcatamney/gpdb,kmjungersen/PostgresXL,tpostgres-projects/tPostgres,snaga/postgres-xl,tpostgres-projects/tPostgres,lisakowen/gpdb,xinzweb/gpdb,snaga/postgres-xl,kmjungersen/PostgresXL,xinzweb/gpdb,ovr/postgres-xl,zeroae/postgres-xl,pavanvd/postgres-xl,techdragon/Postgres-XL,pavanvd/postgres-xl,techdragon/Postgres-XL,ovr/postgres-xl,adam8157/gpdb,yazun/postgres-xl,xinzweb/gpdb,ashwinstar/gpdb,yazun/postgres-xl,jmcatamney/gpdb,50wu/gpdb,ashwinstar/gpdb,arcivanov/postgres-xl,xinzweb/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,tpostgres-projects/tPostgres,ovr/postgres-xl,adam8157/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,ashwinstar/gpdb,xinzweb/gpdb,yazun/postgres-xl,adam8157/gpdb,jmcatamney/gpdb,yazun/postgres-xl,lisakowen/gpdb,greenplum-db/gpdb,tpostgres-projects/tPostgres,pavanvd/postgres-xl,zeroae/postgres-xl,lisakowen/gpdb,adam8157/gpdb,Postgres-XL/Postgres-XL,50wu/gpdb,arcivanov/postgres-xl,oberstet/postgres-xl,50wu/gpdb,postmind-net/postgres-xl,lisakowen/gpdb,greenplum-db/gpdb,snaga/postgres-xl,arcivanov/postgres-xl,postmind-net/postgres-xl,greenplum-db/gpdb,oberstet/postgres-xl,techdragon/Postgres-XL,arcivanov/postgres-xl,kmjungersen/PostgresXL,lisakowen/gpdb,adam8157/gpdb,zeroae/postgres-xl,kmjungersen/PostgresXL,ashwinstar/gpdb,zeroae/postgres-xl,adam8157/gpdb,zeroae/postgres-xl,ovr/postgres-xl,ashwinstar/gpdb,pavanvd/postgres-xl,ashwinstar/gpdb,postmind-net/postgres-xl,Postgres-XL/Postgres-XL,jmcatamney/gpdb,Postgres-XL/Postgres-XL,50wu/gpdb,postmind-net/postgres-xl,adam8157/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,arcivanov/postgres-xl,oberstet/postgres-xl,techdragon/Postgres-XL,adam8157/gpdb,greenplum-db/gpdb,lisakowen/gpdb,yazun/postgres-xl,ashwinstar/gpdb,50wu/gpdb,xinzweb/gpdb,jmcatamney/gpdb,postmind-net/postgres-xl