[Finder] document array use for locations

Author: mickaelandrieu

components/finder.rst

@@ -82,7 +82,7 @@ directory to use for the search::
 Search in several locations by chaining calls to
 :method:`Symfony\\Component\\Finder\\Finder::in`::
 
-    $finder->files()->in(__DIR__)->in('/elsewhere');
+    $finder->files()->in(array(__DIR__, '/elsewhere'));
 
 Use wildcard characters to search in the directories matching a pattern::