minor #7569 [Form] Fixed by_reference option with explicit cloning (HeahDude)

This PR was merged into the 2.7 branch.

Discussion
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[Form] Fixed by_reference option with explicit cloning

Commits
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195ed65 [Form] Fixed by_reference option with explicit cloning

Author: xabbuh

reference/forms/types/options/by_reference.rst.inc

@@ -31,7 +31,7 @@ Notice that ``setAuthor()`` is not called. The author is modified by reference.
 If you set ``by_reference`` to false, submitting looks like this::
 
     $article->setTitle('...');
-    $author = $article->getAuthor();
+    $author = clone $article->getAuthor();
     $author->setName('...');
     $author->setEmail('...');
     $article->setAuthor($author);