doc: testing lambdas

site/_layouts/doc.liquid

@@ -432,6 +432,7 @@
                       <a href="#" class="sub-menu">Lambdas <i class="fal fa-chevron-{% if page.url contains "/lambdas/" %}up{% else %}down{% endif %} fa-fw"></i></a>
                       <ul>
                         <li {% if page.url == "/docs/v1/tech/lambdas/" %}class="active"{% endif %}><a href="/docs/v1/tech/lambdas/">Overview</a></li>
+                        <li {% if page.url == "/docs/v1/tech/lambdas/testing-lambdas.html" %}class="active"{% endif %}><a href="/docs/v1/tech/lambdas/testing-lambdas">Testing Lambdas</a></li>
                         {% comment %}Don't add a new lambda here. Add it to the site/_data/lambdas.yaml file and the menu item will be generated.{% endcomment %}
                         {% assign lambdas = site.data.lambdas | sort: 'displayName' %}
                         {% for lambda in lambdas %}