docs:  remove "III" version text from pgAdmin link
docs:  remove "III" version text from pgAdmin link

Reported-by: vodevsh@gmail.com

Discussion: https://postgr.es/m/152404286919.19366.7988650271505173666@wrigleys.postgresql.org

Backpatch-through: 9.3

50wu/gpdb,greenplum-db/gpdb,xinzweb/gpdb,adam8157/gpdb,greenplum-db/gpdb,xinzweb/gpdb,xinzweb/gpdb,adam8157/gpdb,lisakowen/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,adam8157/gpdb,lisakowen/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,adam8157/gpdb,ashwinstar/gpdb,xinzweb/gpdb,lisakowen/gpdb,50wu/gpdb,adam8157/gpdb,adam8157/gpdb,50wu/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,lisakowen/gpdb,lisakowen/gpdb,50wu/gpdb,ashwinstar/gpdb,adam8157/gpdb,greenplum-db/gpdb,50wu/gpdb,50wu/gpdb,xinzweb/gpdb,xinzweb/gpdb,lisakowen/gpdb,50wu/gpdb,jmcatamney/gpdb,lisakowen/gpdb,ashwinstar/gpdb,lisakowen/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,50wu/gpdb,xinzweb/gpdb,jmcatamney/gpdb,xinzweb/gpdb,adam8157/gpdb,ashwinstar/gpdb