Update misleading comment about RFC4627

RFC 4627 does not dictate escaping of HTML special characters

src/Symfony/Component/HttpFoundation/JsonResponse.php

@@ -27,7 +27,7 @@ class JsonResponse extends Response
     protected $data;
     protected $callback;
 
-    // Encode <, >, ', &, and " for RFC4627-compliant JSON, which may also be embedded into HTML.
+    // Encode <, >, ', &, and " characters in the JSON, making it also safe to be embedded into HTML.
     // 15 === JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT
     protected $encodingOptions = 15;