Minor improvements to the tablespace documentation.
Minor improvements to the tablespace documentation.

rubikloud/gpdb,0x0FFF/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,Chibin/gpdb,ashwinstar/gpdb,cjcjameson/gpdb,xuegang/gpdb,arcivanov/postgres-xl,foyzur/gpdb,adam8157/gpdb,ashwinstar/gpdb,chrishajas/gpdb,randomtask1155/gpdb,tangp3/gpdb,0x0FFF/gpdb,xinzweb/gpdb,techdragon/Postgres-XL,lintzc/gpdb,tpostgres-projects/tPostgres,yuanzhao/gpdb,foyzur/gpdb,greenplum-db/gpdb,Postgres-XL/Postgres-XL,adam8157/gpdb,randomtask1155/gpdb,zeroae/postgres-xl,tangp3/gpdb,kaknikhil/gpdb,yuanzhao/gpdb,ahachete/gpdb,ahachete/gpdb,zaksoup/gpdb,techdragon/Postgres-XL,lintzc/gpdb,ahachete/gpdb,ovr/postgres-xl,Chibin/gpdb,zaksoup/gpdb,yazun/postgres-xl,kaknikhil/gpdb,Postgres-XL/Postgres-XL,lpetrov-pivotal/gpdb,cjcjameson/gpdb,xuegang/gpdb,rubikloud/gpdb,tangp3/gpdb,50wu/gpdb,kaknikhil/gpdb,postmind-net/postgres-xl,adam8157/gpdb,kmjungersen/PostgresXL,janebeckman/gpdb,atris/gpdb,snaga/postgres-xl,yazun/postgres-xl,arcivanov/postgres-xl,ovr/postgres-xl,xinzweb/gpdb,tangp3/gpdb,atris/gpdb,edespino/gpdb,cjcjameson/gpdb,CraigHarris/gpdb,lintzc/gpdb,randomtask1155/gpdb,xinzweb/gpdb,royc1/gpdb,lisakowen/gpdb,kaknikhil/gpdb,lpetrov-pivotal/gpdb,edespino/gpdb,Chibin/gpdb,arcivanov/postgres-xl,CraigHarris/gpdb,Chibin/gpdb,foyzur/gpdb,rubikloud/gpdb,xuegang/gpdb,cjcjameson/gpdb,greenplum-db/gpdb,rvs/gpdb,atris/gpdb,Quikling/gpdb,royc1/gpdb,xinzweb/gpdb,jmcatamney/gpdb,edespino/gpdb,Quikling/gpdb,zeroae/postgres-xl,jmcatamney/gpdb,foyzur/gpdb,kaknikhil/gpdb,xuegang/gpdb,janebeckman/gpdb,chrishajas/gpdb,Postgres-XL/Postgres-XL,xuegang/gpdb,yazun/postgres-xl,tpostgres-projects/tPostgres,xinzweb/gpdb,zaksoup/gpdb,oberstet/postgres-xl,ahachete/gpdb,lintzc/gpdb,lpetrov-pivotal/gpdb,kmjungersen/PostgresXL,royc1/gpdb,jmcatamney/gpdb,techdragon/Postgres-XL,50wu/gpdb,ashwinstar/gpdb,xinzweb/gpdb,janebeckman/gpdb,Quikling/gpdb,0x0FFF/gpdb,yazun/postgres-xl,Quikling/gpdb,CraigHarris/gpdb,zaksoup/gpdb,50wu/gpdb,cjcjameson/gpdb,Quikling/gpdb,50wu/gpdb,ovr/postgres-xl,chrishajas/gpdb,Quikling/gpdb,randomtask1155/gpdb,atris/gpdb,zeroae/postgres-xl,kmjungersen/PostgresXL,adam8157/gpdb,pavanvd/postgres-xl,royc1/gpdb,techdragon/Postgres-XL,lpetrov-pivotal/gpdb,ahachete/gpdb,zaksoup/gpdb,greenplum-db/gpdb,pavanvd/postgres-xl,Chibin/gpdb,kaknikhil/gpdb,0x0FFF/gpdb,tangp3/gpdb,oberstet/postgres-xl,rubikloud/gpdb,cjcjameson/gpdb,oberstet/postgres-xl,0x0FFF/gpdb,chrishajas/gpdb,chrishajas/gpdb,rubikloud/gpdb,rvs/gpdb,foyzur/gpdb,royc1/gpdb,lpetrov-pivotal/gpdb,rvs/gpdb,chrishajas/gpdb,ashwinstar/gpdb,yazun/postgres-xl,janebeckman/gpdb,xuegang/gpdb,Chibin/gpdb,zaksoup/gpdb,arcivanov/postgres-xl,CraigHarris/gpdb,foyzur/gpdb,yuanzhao/gpdb,tpostgres-projects/tPostgres,xinzweb/gpdb,rvs/gpdb,xuegang/gpdb,CraigHarris/gpdb,janebeckman/gpdb,royc1/gpdb,50wu/gpdb,edespino/gpdb,ahachete/gpdb,lisakowen/gpdb,ovr/postgres-xl,rubikloud/gpdb,tangp3/gpdb,zaksoup/gpdb,kaknikhil/gpdb,yuanzhao/gpdb,CraigHarris/gpdb,rvs/gpdb,Postgres-XL/Postgres-XL,Chibin/gpdb,kaknikhil/gpdb,foyzur/gpdb,adam8157/gpdb,lisakowen/gpdb,janebeckman/gpdb,ovr/postgres-xl,arcivanov/postgres-xl,Quikling/gpdb,kaknikhil/gpdb,CraigHarris/gpdb,adam8157/gpdb,Quikling/gpdb,oberstet/postgres-xl,edespino/gpdb,rvs/gpdb,cjcjameson/gpdb,janebeckman/gpdb,CraigHarris/gpdb,50wu/gpdb,arcivanov/postgres-xl,kaknikhil/gpdb,lintzc/gpdb,edespino/gpdb,snaga/postgres-xl,0x0FFF/gpdb,CraigHarris/gpdb,postmind-net/postgres-xl,greenplum-db/gpdb,lisakowen/gpdb,pavanvd/postgres-xl,atris/gpdb,edespino/gpdb,rvs/gpdb,kmjungersen/PostgresXL,0x0FFF/gpdb,rvs/gpdb,50wu/gpdb,snaga/postgres-xl,Chibin/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,0x0FFF/gpdb,cjcjameson/gpdb,royc1/gpdb,Postgres-XL/Postgres-XL,atris/gpdb,edespino/gpdb,jmcatamney/gpdb,randomtask1155/gpdb,tpostgres-projects/tPostgres,tangp3/gpdb,xinzweb/gpdb,chrishajas/gpdb,lintzc/gpdb,cjcjameson/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,cjcjameson/gpdb,postmind-net/postgres-xl,jmcatamney/gpdb,randomtask1155/gpdb,yuanzhao/gpdb,janebeckman/gpdb,chrishajas/gpdb,Quikling/gpdb,tangp3/gpdb,rubikloud/gpdb,yuanzhao/gpdb,techdragon/Postgres-XL,zeroae/postgres-xl,lpetrov-pivotal/gpdb,atris/gpdb,lintzc/gpdb,rubikloud/gpdb,pavanvd/postgres-xl,lintzc/gpdb,ahachete/gpdb,pavanvd/postgres-xl,rvs/gpdb,xuegang/gpdb,randomtask1155/gpdb,yuanzhao/gpdb,rvs/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,xuegang/gpdb,snaga/postgres-xl,edespino/gpdb,lisakowen/gpdb,atris/gpdb,royc1/gpdb,ahachete/gpdb,randomtask1155/gpdb,postmind-net/postgres-xl,lisakowen/gpdb,ashwinstar/gpdb,lisakowen/gpdb,lintzc/gpdb,jmcatamney/gpdb,edespino/gpdb,zaksoup/gpdb,lpetrov-pivotal/gpdb,lisakowen/gpdb,zeroae/postgres-xl,snaga/postgres-xl,tpostgres-projects/tPostgres,janebeckman/gpdb,Chibin/gpdb,ashwinstar/gpdb,postmind-net/postgres-xl,ashwinstar/gpdb,foyzur/gpdb,lpetrov-pivotal/gpdb,yuanzhao/gpdb,50wu/gpdb,Chibin/gpdb,greenplum-db/gpdb,kmjungersen/PostgresXL,janebeckman/gpdb,adam8157/gpdb,adam8157/gpdb,Quikling/gpdb