Change example URL from http to https protocol

Author: delphidabbler

Docs/Design/FileFormats/main-db.html

@@ -933,7 +933,7 @@ <h2>
       Here is an example of how the <code class="key">Credits</code> and <code  class="key">Credits_URL</code> key work together.
     </p>
     <p>
-    If <code class="key">Credits</code>=<code class="value">&quot;See [example]&quot;</code> and <code class="key">Credits_URL</code>=<code class="value">&quot;http://example.com&quot;</code> and the <code class="key">Extra</code> key is empty or missing then the extra text generated will be <samp>See &lt;a href=&quot;example.com&quot;&gt;example 1&lt;/a&gt;</samp>.
+    If <code class="key">Credits</code>=<code class="value">&quot;See [example]&quot;</code> and <code class="key">Credits_URL</code>=<code class="value">&quot;https://example.com&quot;</code> and the <code class="key">Extra</code> key is empty or missing then the extra text generated will be <samp>See &lt;a href=&quot;example.com&quot;&gt;example 1&lt;/a&gt;</samp>.
     </p>
   </li>
   <li id="footnote-3">