Publish post 'Test nginx Configuration Directives' (#3)

Sitegen had some problems rendering `$host$request_uri` and `$$ct` so I had to make some changes to the Markdown renderer.

Reviewed-on: #3

spec/nginx_spec.moon

@@ -104,6 +104,10 @@ describe "https://miti.sh/posts/", ->
 
 describe "https://miti.sh/posts", ->
   it "sends /posts/index.html", ->
+    with require "sitegen.path"
+      assert .exists("html/posts/index.html"),
+        "missing html/posts/index.html (try `make build file=blog.html`)"
+
     request = req "https://miti.sh/posts"
     assert.same request\statusCode!, 200
     assert.same request\statusMessage!, "OK"

spec/renderers_spec.moon

@@ -86,3 +86,11 @@ this code block has no label
 
       assert.same [[<div class="sourceCode" id="cb1"><pre
 class="sourceCode heex"><code class="sourceCode elixir"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="op">&lt;.</span>greet name<span class="op">=</span><span class="st">&quot;Jane&quot;</span><span class="op">/&gt;</span></span></code></pre></div>]], out
+
+    it "escapes and unescapes double dollar signs", ->
+      out = flatten_html render [[
+```Makefile
+  $$name
+```]]
+
+      assert.same [[<div class="highlight"><pre><span></span><code><span class="py-w"></span><span class="py-nv">$$name</span></code></pre></div>]], out