minor #4829 Fix code example (ifdattic)

This PR was merged into the 2.5 branch.

Discussion
----------

Fix code example

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.5
| Fixed tickets |

Commits
-------

7970f76 Fix code example

cookbook/bundles/best_practices.rst

@@ -369,8 +369,8 @@ API is being used. The following code, would work for *all* users::
                 // the 2.5 API
                 $this->context->buildViolation($constraint->message)
                     ->setParameter('%string%', $value)
-                    ->addViolation();
-                );
+                    ->addViolation()
+                ;
             } else {
                 // the 2.4 API
                 $this->context->addViolation(