Fix broken getting started link

Backport of napari/docs#217

0.4.18/tutorials/start_index.html

@@ -1199,7 +1199,7 @@ <h1>Getting started<a class="headerlink" href="#getting-started" title="Permalin
 Getting started</div>
 <p class="sd-card-text">This tutorial will teach you all the different ways to launch napari.</p>
 </div>
-<a class="sd-stretched-link reference external" href="https://docs.python.org/3/library/unittest.mock-examples.html#getting-started" title="(in Python v3.11)"><span></span></a></div>
+<a class="sd-stretched-link reference internal" href="fundamentals/getting_started.html#getting-started"><span class="std std-ref"></span></a></div>
 </div>
 </div>
 </div>