Move to custom SSG instead of eleventy.

docs/renderer/nodes/CodeBlock.njk

@@ -0,0 +1,9 @@
+{% macro render(node) %}
+  <pre
+    class="
+      my-8 p-4
+      bg-neutral-900 text-neutral-50 rounded-md whitespace-pre-wrap text-sm
+      {{ node.class }}
+    "
+  >{{ node.text | highlight(node.language) | safe }}</pre>
+{% endmacro %}