minor #4359 Added missing closing parenthesis to example. (mattjanssen)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #4359).

Discussion
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Added missing closing parenthesis to example.

Commits
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d1bfa91 Added missing closing parenthesis to example.

components/form/introduction.rst

@@ -514,7 +514,7 @@ by ``handleRequest()`` to determine whether a form has been submitted):
         $formBuilder = $formFactory->createBuilder('form', null, array(
             'action' => '/search',
             'method' => 'GET',
-        );
+        ));
 
         // ...