Update mpl_sphinx_theme/mpl_nav_bar.html

Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com>

Author: story645

mpl_sphinx_theme/mpl_nav_bar.html

@@ -11,7 +11,7 @@
   <li class="nav-item">
     <a class="reference internal nav-link" href="{{ mpl_path('gallery/index') }}">Examples</a>
   </li>
-   <li class="nav-item">
+  <li class="nav-item">
     <a class="reference internal nav-link" href="{{ mpl_path('api/index') }}">Reference</a>
   </li>
   <li class="nav-item">