Improve formatting of --help output.

src/backend/postmaster/postmaster.c

src/backend/tcop/postgres.c

src/bin/initdb/initdb.sh

src/bin/initlocation/initlocation.sh

src/bin/ipcclean/ipcclean.sh

src/bin/pg_config/pg_config.sh

src/bin/pg_controldata/pg_controldata.c

src/bin/pg_ctl/pg_ctl.sh

src/bin/pg_dump/pg_dump.c

src/bin/pg_dump/pg_dumpall.c

src/bin/pg_dump/pg_restore.c

src/bin/pg_resetxlog/pg_resetxlog.c

src/bin/psql/help.c

src/bin/psql/startup.c

src/bin/scripts/clusterdb

src/bin/scripts/createdb

src/bin/scripts/createlang.sh

src/bin/scripts/createuser

src/bin/scripts/dropdb

src/bin/scripts/droplang