Merge branch '4.4' into 5.2

* 4.4:
  Fix invalid file

Author: javiereguiluz

http_client.rst

@@ -550,9 +550,7 @@ Use the ``headers`` option to define the default headers added to all requests:
             ],
         ]);
 
-You can also set new headers or override the default ones for specific requests:
-
-.. code-block:: php
+You can also set new headers or override the default ones for specific requests::
 
     // this header is only included in this request and overrides the value
     // of the same header if defined globally by the HTTP client