Maintenance: Fix EventScheduler::timeRemaining() comment (#1916)

src/event.cc

@@ -204,7 +204,7 @@ EventScheduler::timeRemaining() const
     if (tasks->when <= current_dtime) // we are on time or late
         return 0; // fire the event ASAP
 
-    const double diff = tasks->when - current_dtime; // microseconds
+    const double diff = tasks->when - current_dtime; // seconds
     // Round UP: If we come back a nanosecond earlier, we will wait again!
     const int timeLeft = static_cast<int>(ceil(1000*diff)); // milliseconds
     // Avoid hot idle: A series of rapid select() calls with zero timeout.