Update documentation for tsvector duplicate elimination:
Update documentation for tsvector duplicate elimination:

!      Duplicate positions for the same lexeme are discarded.

zeroae/postgres-xl,rvs/gpdb,50wu/gpdb,CraigHarris/gpdb,kaknikhil/gpdb,xuegang/gpdb,yuanzhao/gpdb,xuegang/gpdb,tpostgres-projects/tPostgres,pavanvd/postgres-xl,xinzweb/gpdb,kmjungersen/PostgresXL,royc1/gpdb,chrishajas/gpdb,rvs/gpdb,royc1/gpdb,CraigHarris/gpdb,yuanzhao/gpdb,adam8157/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,arcivanov/postgres-xl,ashwinstar/gpdb,zaksoup/gpdb,CraigHarris/gpdb,cjcjameson/gpdb,tpostgres-projects/tPostgres,ahachete/gpdb,yuanzhao/gpdb,xuegang/gpdb,Postgres-XL/Postgres-XL,cjcjameson/gpdb,zaksoup/gpdb,tpostgres-projects/tPostgres,lintzc/gpdb,rvs/gpdb,yazun/postgres-xl,Quikling/gpdb,rvs/gpdb,janebeckman/gpdb,greenplum-db/gpdb,lintzc/gpdb,techdragon/Postgres-XL,royc1/gpdb,edespino/gpdb,xinzweb/gpdb,chrishajas/gpdb,ashwinstar/gpdb,xinzweb/gpdb,postmind-net/postgres-xl,xuegang/gpdb,rvs/gpdb,greenplum-db/gpdb,ovr/postgres-xl,snaga/postgres-xl,kaknikhil/gpdb,greenplum-db/gpdb,ahachete/gpdb,ashwinstar/gpdb,janebeckman/gpdb,snaga/postgres-xl,ahachete/gpdb,adam8157/gpdb,ahachete/gpdb,ovr/postgres-xl,Chibin/gpdb,cjcjameson/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,arcivanov/postgres-xl,xuegang/gpdb,edespino/gpdb,adam8157/gpdb,cjcjameson/gpdb,postmind-net/postgres-xl,yuanzhao/gpdb,adam8157/gpdb,royc1/gpdb,yazun/postgres-xl,ashwinstar/gpdb,CraigHarris/gpdb,Postgres-XL/Postgres-XL,Chibin/gpdb,Chibin/gpdb,Postgres-XL/Postgres-XL,jmcatamney/gpdb,royc1/gpdb,ashwinstar/gpdb,chrishajas/gpdb,janebeckman/gpdb,0x0FFF/gpdb,Chibin/gpdb,lisakowen/gpdb,edespino/gpdb,zaksoup/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,Chibin/gpdb,Chibin/gpdb,Quikling/gpdb,kaknikhil/gpdb,arcivanov/postgres-xl,yazun/postgres-xl,janebeckman/gpdb,kaknikhil/gpdb,edespino/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,lisakowen/gpdb,zaksoup/gpdb,zaksoup/gpdb,yuanzhao/gpdb,kmjungersen/PostgresXL,oberstet/postgres-xl,techdragon/Postgres-XL,janebeckman/gpdb,lintzc/gpdb,royc1/gpdb,50wu/gpdb,janebeckman/gpdb,chrishajas/gpdb,xuegang/gpdb,CraigHarris/gpdb,0x0FFF/gpdb,zaksoup/gpdb,lintzc/gpdb,Chibin/gpdb,rvs/gpdb,Chibin/gpdb,adam8157/gpdb,lintzc/gpdb,adam8157/gpdb,postmind-net/postgres-xl,yuanzhao/gpdb,Quikling/gpdb,oberstet/postgres-xl,CraigHarris/gpdb,techdragon/Postgres-XL,greenplum-db/gpdb,ovr/postgres-xl,snaga/postgres-xl,zeroae/postgres-xl,Postgres-XL/Postgres-XL,zeroae/postgres-xl,yuanzhao/gpdb,lisakowen/gpdb,xuegang/gpdb,50wu/gpdb,50wu/gpdb,janebeckman/gpdb,ahachete/gpdb,50wu/gpdb,CraigHarris/gpdb,0x0FFF/gpdb,Quikling/gpdb,jmcatamney/gpdb,snaga/postgres-xl,lisakowen/gpdb,Chibin/gpdb,pavanvd/postgres-xl,xinzweb/gpdb,cjcjameson/gpdb,ahachete/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,lintzc/gpdb,Quikling/gpdb,lintzc/gpdb,Quikling/gpdb,xuegang/gpdb,cjcjameson/gpdb,50wu/gpdb,xuegang/gpdb,Quikling/gpdb,0x0FFF/gpdb,pavanvd/postgres-xl,kmjungersen/PostgresXL,janebeckman/gpdb,arcivanov/postgres-xl,rvs/gpdb,rvs/gpdb,pavanvd/postgres-xl,ovr/postgres-xl,xinzweb/gpdb,50wu/gpdb,kaknikhil/gpdb,arcivanov/postgres-xl,kaknikhil/gpdb,edespino/gpdb,chrishajas/gpdb,Quikling/gpdb,oberstet/postgres-xl,kmjungersen/PostgresXL,yazun/postgres-xl,oberstet/postgres-xl,jmcatamney/gpdb,arcivanov/postgres-xl,jmcatamney/gpdb,cjcjameson/gpdb,zaksoup/gpdb,techdragon/Postgres-XL,0x0FFF/gpdb,yazun/postgres-xl,pavanvd/postgres-xl,jmcatamney/gpdb,greenplum-db/gpdb,Postgres-XL/Postgres-XL,jmcatamney/gpdb,lintzc/gpdb,kmjungersen/PostgresXL,janebeckman/gpdb,0x0FFF/gpdb,chrishajas/gpdb,lisakowen/gpdb,kaknikhil/gpdb,xinzweb/gpdb,Chibin/gpdb,CraigHarris/gpdb,lisakowen/gpdb,tpostgres-projects/tPostgres,greenplum-db/gpdb,chrishajas/gpdb,Quikling/gpdb,lintzc/gpdb,ovr/postgres-xl,oberstet/postgres-xl,lisakowen/gpdb,adam8157/gpdb,0x0FFF/gpdb,edespino/gpdb,adam8157/gpdb,ahachete/gpdb,greenplum-db/gpdb,zeroae/postgres-xl,snaga/postgres-xl,janebeckman/gpdb,yuanzhao/gpdb,techdragon/Postgres-XL,xinzweb/gpdb,zaksoup/gpdb,Quikling/gpdb,0x0FFF/gpdb,postmind-net/postgres-xl,xinzweb/gpdb,jmcatamney/gpdb,zeroae/postgres-xl,lisakowen/gpdb,rvs/gpdb,tpostgres-projects/tPostgres,kaknikhil/gpdb,edespino/gpdb,ahachete/gpdb,chrishajas/gpdb,50wu/gpdb,edespino/gpdb,postmind-net/postgres-xl,royc1/gpdb,edespino/gpdb,royc1/gpdb,CraigHarris/gpdb,rvs/gpdb,edespino/gpdb,kaknikhil/gpdb