[BrowserKit] marked Response as @final

UPGRADE-4.3.md

@@ -4,6 +4,7 @@ UPGRADE FROM 4.2 to 4.3
 BrowserKit
 ----------
 
+ * Marked `Response` final.
  * Deprecated `Response::buildHeader()`
  * Deprecated `Response::getStatus()`, use `Response::getStatusCode()` instead
 

UPGRADE-5.0.md

@@ -4,6 +4,7 @@ UPGRADE FROM 4.x to 5.0
 BrowserKit
 ----------
 
+ * Removed the possibility to extend `Response` by making it final.
  * Removed `Response::buildHeader()`
  * Removed `Response::getStatus()`, use `Response::getStatusCode()` instead
  * The `Client::submit()` method has a new `$serverParameters` argument.

src/Symfony/Component/BrowserKit/CHANGELOG.md

@@ -4,6 +4,7 @@ CHANGELOG
 4.3.0
 -----
 
+ * Marked `Response` final.
  * Deprecated `Response::buildHeader()`
  * Deprecated `Response::getStatus()`, use `Response::getStatusCode()` instead
 

src/Symfony/Component/BrowserKit/Response.php

@@ -13,11 +13,16 @@ namespace Symfony\Component\BrowserKit;
 
 /**
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @final since Symfony 4.3
  */
 class Response
 {
+    /** @internal */
     protected $content;
+    /** @internal */
     protected $status;
+    /** @internal */
     protected $headers;
 
     /**