Slightly improve initdb --sync-only option's help message

When Who What
2021-08-23 11:10:21 Gurjeet Singh (gurjeet) Changed reviewers to Daniel Gustafsson (d_gustafsson), Nathan Bossart (bossartn)
2021-08-22 23:45:35 Cindy Quintana (quintanacindy063.gmail.com) Added quintanacindy063.gmail.com as reviewer
2021-08-16 11:42:53 Daniel Gustafsson (d_gustafsson) Closed in commitfest 2021-09 with status: Committed
2021-08-16 11:42:45 Daniel Gustafsson (d_gustafsson) Added d_gustafsson as committer
2021-08-16 11:42:44 Daniel Gustafsson (d_gustafsson) Added d_gustafsson as reviewer
2021-07-22 22:32:41 Nathan Bossart (bossartn) Added bossartn as reviewer
2021-07-07 02:25:58 Gurjeet Singh (gurjeet) Changed authors to Gurjeet Singh (gurjeet)
2021-07-07 02:25:40 Gurjeet Singh (gurjeet) Attached mail thread CABwTF4U6hbNNE1bv=LxQdJybmUdZ5NJQ9rKY9tN82NXM8QH+iQ@mail.gmail.com
2021-07-07 02:25:40 Gurjeet Singh (gurjeet) Created patch record