Merge branch '6.3' into 6.4

* 6.3:
  [Finder] Fix initial directory is opened twice
  typo fix
  Fix test
  Fix some return types in tests

Author: nicolas-grekas

Tests/Functional/app/AppKernel.php

@@ -89,7 +89,7 @@ public function __sleep(): array
         return ['varDir', 'testCase', 'rootConfig', 'environment', 'debug'];
     }
 
-    public function __wakeup()
+    public function __wakeup(): void
     {
         foreach ($this as $k => $v) {
             if (\is_object($v)) {

Tests/Kernel/ConcreteMicroKernel.php

@@ -68,7 +68,7 @@ public function __sleep(): array
         throw new \BadMethodCallException('Cannot serialize '.__CLASS__);
     }
 
-    public function __wakeup()
+    public function __wakeup(): void
     {
         throw new \BadMethodCallException('Cannot unserialize '.__CLASS__);
     }

Tests/Kernel/flex-style/src/FlexStyleMicroKernel.php

@@ -69,7 +69,7 @@ public function __sleep(): array
         throw new \BadMethodCallException('Cannot serialize '.__CLASS__);
     }
 
-    public function __wakeup()
+    public function __wakeup(): void
     {
         throw new \BadMethodCallException('Cannot unserialize '.__CLASS__);
     }