Allow to search by Guest's name, with no content search text

[Kazakh]

Very often you need to find all the posts from a specific Guest, who does not use the same IP adresses.

For example,  some user deletes their account - so all their messages become "Guest", with a specific Guest name. Currently, there is no way to locate all the messages from this user.

Or some Guest floods your forum with nonsense from different IP addresses, but the same Guest name (happened to me). It is currently not possible to locate and remove such messages.

And, sometimes you just want to see all the posts from a regular unregistered Guest... And you currently can't.