Add types to private and internal properties

Author: nicolas-grekas

Request.php

@@ -766,7 +766,7 @@ public function setSession(SessionInterface $session)
      */
     public function setSessionFactory(callable $factory): void
     {
-        $this->session = $factory;
+        $this->session = $factory(...);
     }
 
     /**

Response.php

@@ -503,12 +503,6 @@ public function setStatusCode(int $code, string $text = null): static
             return $this;
         }
 
-        if (false === $text) {
-            $this->statusText = '';
-
-            return $this;
-        }
-
         $this->statusText = $text;
 
         return $this;