When calling a relay overloaded, give a timestamp too

Right now it appears that the relay-search page just says "it is overloaded" without more specifics.

But there are many confused relay operators on the list and on irc wondering whether they have fixed whatever caused the overload, since they changed stuff but relay-search still says it.

Would it help to put a timestamp on the message on relay-search, so they at least know if the relay has continued to say that it's overloaded after they changed stuff?

I guess this is also related to the timeframe where the Tor process will report overload from the past -- i.e. it is not just about the descriptor timestamp, it is about that plus knowing for how long into the future the relay will continue reporting about past problems (cc @dgoulet).