docs: update link to index.html.twig in customization.rst (#2316)

the link that was there no longer worked, it led to a file that hadn't
existed for a while, so I updated it

![image](https://github.com/user-attachments/assets/9ce4ad6d-d037-4270-8aca-0cade6900640)

| Q | A |

|---------------|---------------------------------------------------------------------------------------------------------------------------|
| Bug fix? | yes |
| New feature? | no |
| Deprecations? | yes |

docs/customization.rst

@@ -68,4 +68,4 @@ Just create a file ``templates/bundles/NelmioApiDocBundle/SwaggerUi/index.html.t
         <script type="text/javascript" src="{{ asset('js/custom-request-signer.js') }}"></script>
     {% endblock javascripts %}
 
-You can have a look at the `original template <https://github.com/nelmio/NelmioApiDocBundle/blob/master/Resources/views/SwaggerUi/index.html.twig>`_, in ``/Resources/views/SwaggerUi/index.html.twig``, to see which blocks can be overridden.
+You can have a look at the `original template <https://github.com/nelmio/NelmioApiDocBundle/blob/master/templates/SwaggerUi/index.html.twig>`_, in ``/templates/SwaggerUi/index.html.twig``, to see which blocks can be overridden.