Fix missing search results (#1591)

Fixes #1490

Reference issues:
- jekyll/jemoji#43
- jekyll/jekyll-mentions#51

Author: fertolg

src/search.html

@@ -0,0 +1,21 @@
+---
+title: Search
+---
+
+<div class="d-flex">
+    <script>
+        (function() {
+            var cx = '007067728241810524621:gm6vraqlc8c';
+            var gcse = document.createElement('script');
+            gcse.type = 'text/javascript';
+            gcse.async = true;
+            gcse.src = (document.location.protocol == 'https:' ? 'https:' : 'http:') +
+                '//cse.google.com/cse.js?cx=' + cx;
+            var s = document.getElementsByTagName('script')[0];
+            s.parentNode.insertBefore(gcse, s);
+        })();
+    </script>
+    <script type="text/javascript">
+        document.write("<gcse:search></gcse:search>");
+    </script>
+</div>