Fix initial visibility of second-pass hint markers

Fix initial visibility of second-pass hint markers

1. Go to a site where there is a noticeable delay between the two passes
   for the `f` command, such as on reddit.com.
2. Press a prefix hint char there before the second pass has completed.

When the second pass completes, the hint markers for that pass will be
shown, even though they cannot start with the prefix hint char you
pressed. This commit makes sure that the hint markers for the second
pass start out hidden if needed.