minor #4887 Typo (XitasoChris)

This PR was merged into the 2.6 branch.

Discussion
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Typo

Typo: is -> id

Commits
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9edffa0 Typo

cookbook/form/form_collections.rst

@@ -681,7 +681,7 @@ the relationship between the removed ``Tag`` and ``Task`` object.
             $task = $em->getRepository('AcmeTaskBundle:Task')->find($id);
 
             if (!$task) {
-                throw $this->createNotFoundException('No task found for is '.$id);
+                throw $this->createNotFoundException('No task found for id '.$id);
             }
 
             $originalTags = new ArrayCollection();