Remove useless regex for redirecting /ghost -> /ghost/

The `\/?` is useless in the regex `/\/(ghost$\/?)/`. Since `$` must match, and since it represents the end of the string, it means `\/?` will never be used, and thus the regex is equivalent to `/\/(ghost$)/`, which is equivalent to `/\/ghost$/`, which is simply just the string `/ghost`.

This change makes that more obvious in the code, as it may not be immediately obvious what `/\/(ghost$\/?)/` means.