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()

User/UserInterface.php

@@ -55,7 +55,7 @@ public function getRoles(): array;
     public function eraseCredentials();
 
     /**
-     * Returns the identifier for this user (e.g. its username or email address).
+     * Returns the identifier for this user (e.g. username or email address).
      */
     public function getUserIdentifier(): string;
 }