minor symfony#6213 Update form_collections.rst (insekticid)

This PR was submitted for the 3.0 branch but it was merged into the 2.8 branch instead (closes symfony#6213).

Discussion
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Update form_collections.rst

removed new from new TaskType::class

Commits
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bb96dc6 Update form_collections.rst

Author: xabbuh

Diff for: cookbook/form/form_collections.rst

@@ -689,7 +689,7 @@ the relationship between the removed ``Tag`` and ``Task`` object.
                 $originalTags->add($tag);
             }
 
-            $editForm = $this->createForm(new TaskType::class, $task);
+            $editForm = $this->createForm(TaskType::class, $task);
 
             $editForm->handleRequest($request);