Merge branch '6.0' into 6.1

* 6.0:
  [HttpFoundation] IPv4-mapped IPv6 addresses incorrectly rejected
  Minor (comment only), part 2
  [RateLimiter] Add typecast to Reservation::wait
  [FrameworkBundle] Remove check of undefined service in mailer assertions
  [VarDumper] Ignore \Error in __debugInfo()

Reservation.php

@@ -45,6 +45,6 @@ public function getRateLimit(): RateLimit
 
     public function wait(): void
     {
-        usleep($this->getWaitDuration() * 1e6);
+        usleep((int) ($this->getWaitDuration() * 1e6));
     }
 }