docs: Remove Weights & Biases announcement

Author: holtskinner

.mkdocs/overrides/main.html

@@ -1,10 +1,3 @@
 {% extends "base.html" %}
 
-{% block announce %}
-  <div class="announce">
-    <p>
-      Join us on July 12-13 at the Weights & Biases office in San Francisco for a
-      <a href="https://lu.ma/weavehacks" class="md-button md-button--primary">A2A/MCP Hackathon</a>
-    </p>
-  </div>
-{% endblock %}
+{% block announce %}{% endblock %}