Support for man page links, if a man page has more than one refname.
Support for man page links, if a man page has more than one refname.

We don't actually use this anywhere, but it might come in handy for dealing
with SELECT/WITH/TABLE.

It works with both the old and the new man page target (for some value of
"works").

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