diff --git a/public/help/wiki_syntax_detailed.html b/public/help/wiki_syntax_detailed.html
index 0398e4f..38d5da3 100644
--- a/public/help/wiki_syntax_detailed.html
+++ b/public/help/wiki_syntax_detailed.html
@@ -243,6 +243,12 @@ To go live, all you need to add is a database and a web server.
 {{>toc}} => right aligned toc
 </pre>
 
+        <h3><a name="14" class="wiki-page"></a>Horizontal Rule</h3>
+
+<pre>
+---
+</pre>
+
     <h2><a name="12" class="wiki-page"></a>Macros</h2>
 
     <p>Redmine has the following builtin macros:</p>