[#8471] minor reword

Author: xabbuh

components/dom_crawler.rst

@@ -248,7 +248,7 @@ The crawler supports multiple ways of adding the content::
 
     .. versionadded:: 3.4
         The charset guessing mechanism of the ``addContent()`` method was
-        introduced in Symfony 3.4. In previous Symfony versions, ``ISO-8859-1``
+        introduced in Symfony 3.4. In previous Symfony versions, the ``ISO-8859-1``
         charset was always used.
 
 As the Crawler's implementation is based on the DOM extension, it is also able