Clean up autovacuum documentation, which was a bit out of sync with what the code actually does, and needed copy-editing anyway.  Also take the opportunity to expand the section on routine reindexing.
Clean up autovacuum documentation, which was a bit out of sync with what
the code actually does, and needed copy-editing anyway.  Also take the
opportunity to expand the section on routine reindexing.

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