add new block to overwrite just the content

so you don't need to overwrite the markup

Resources/views/standard_layout.html.twig

@@ -221,7 +221,11 @@ file that was distributed with this source code.
                                 {% endif %}
                             {% endblock side_bar_nav %}
                             {% block side_bar_after_nav %}
-                                <p class="text-center small" style="border-top: 1px solid #444444; padding-top: 10px"><a href="https://sonata-project.org" rel="noreferrer" target="_blank">sonata project</a></p>
+                                <p class="text-center small" style="border-top: 1px solid #444444; padding-top: 10px">
+                                    {% block side_bar_after_nav_content %}
+                                        <a href="https://sonata-project.org" rel="noreferrer" target="_blank">sonata project</a>
+                                    {% endblock %}
+                                </p>
                             {% endblock %}
                         {% endblock sonata_side_nav %}
                     </section>