Merge branch '6.4' into 7.0

* 6.4: (32 commits)
  [Validator] Fix registering "is_valid()" for `#[Expression]`
  [Scheduler] Trigger unique messages at runtime
  [Scheduler] Fix CHANGELOG
  [Clock] Add `DatePoint`: an immutable DateTime implementation with stricter error handling and return types
  [Scheduler] Allow modifying the schedule at runtime and recalculate heap
  [Cache] Fix Redis6Proxy
  [Finder] Disable failing test about open_basedir
  Fix merge
  Fix merge
  Minor CS fixes
  Deprecate `Kernel::stripComments()`
  Remove setAccessible reflection call in tests
  [Notifier] Telegram Bridge add escaping for \
  [Component][AssertMapper] add type hint of an argument in asset mapper command
  [Translation] [Phrase] Refacto ReadConfig and WriteConfig into arrays
  [Routing] Fix routing collection defaults when adding a new route to a collection
  [Messenger] Fix cloned TraceableStack not unstacking the stack independently
  [Translation] Add `--as-tree` option  to `translation:pull` command
  [Mime] Allow to add some headers as a strings
  [Translation] Give current locale to locale switcher runWithLocale callback
  ...

Author: nicolas-grekas

Header/Headers.php

@@ -147,6 +147,8 @@ public function addHeader(string $name, mixed $argument, array $more = []): stat
             $method = 'addTextHeader';
         } elseif ('addIdentificationHeader' === $method) {
             $method = 'addIdHeader';
+        } elseif ('addMailboxListHeader' === $method && !\is_array($argument)) {
+            $argument = [$argument];
         }
 
         return $this->$method($name, $argument, $more);

Tests/Header/HeadersTest.php

@@ -69,6 +69,7 @@ public function testAddHeader()
     {
         $headers = new Headers();
         $headers->addHeader('from', ['[email protected]']);
+        $headers->addHeader('reply-to', '[email protected]');
         $headers->addHeader('return-path', '[email protected]');
         $headers->addHeader('foo', 'bar');
         $headers->addHeader('date', $now = new \DateTimeImmutable());
@@ -77,6 +78,9 @@ public function testAddHeader()
         $this->assertInstanceOf(MailboxListHeader::class, $headers->get('from'));
         $this->assertEquals([new Address('[email protected]')], $headers->get('from')->getBody());
 
+        $this->assertInstanceOf(MailboxListHeader::class, $headers->get('reply-to'));
+        $this->assertEquals([new Address('[email protected]')], $headers->get('reply-to')->getBody());
+
         $this->assertInstanceOf(PathHeader::class, $headers->get('return-path'));
         $this->assertEquals(new Address('[email protected]'), $headers->get('return-path')->getBody());