In order to create parity with the quick search drop-down, we now index
all users and display any matches in the search results. These are shown
with the gravatar (if enabled), full name, username, e-mail address,
groups they're a member of, and a link to their review requests.

These results respect the user's private profile settings.

Tested with different users I have on my server. Saw their entries whenever

I matched the username, e-mail address, or full name.
Tested all links.