Fix typos

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.6
| Fixed tickets |

Author: ifdattic

components/var_dumper/advanced.rst

@@ -20,7 +20,7 @@ like this::
     use Symfony\Component\VarDumper\Dumper\CliDumper;
     use Symfony\Component\VarDumper\Dumper\HtmlDumper;
 
-    VarDumper::setHandler(function($var) {
+    VarDumper::setHandler(function ($var) {
         $cloner = new VarCloner();
         $dumper = 'cli' === PHP_SAPI ? new CliDumper() : new HtmlDumper();