Fix spacing so json example looks nice

Author: andylolz

prefix_finder/frontend/templates/about.html

@@ -45,10 +45,10 @@ <h2 id="data-creators">Data creators</h2>
         <code class="about-page__code">GB-COH-09506232</code>
         <p>Or separating out the list code into it’s own field:</p>
         <p>E.g.</p>
-                <pre><code class="about-page__code">{
-            "scheme": "GB-COH",
-            "id": "09506232
-        }</code></pre>
+        <pre><code class="about-page__code">{
+    "scheme": "GB-COH",
+    "id": "09506232
+}</code></pre>
 
       </div>
       <div class="about-page__half--right">