oast: Address HTML issue in help page

Added the missing closing tag.

Signed-off-by: Umoxfo <[email protected]>

Author: Umoxfo

addOns/oast/src/main/javahelp/org/zaproxy/addon/oast/resources/help/contents/api.html

@@ -58,6 +58,7 @@ <h3>Actions</h3>
 				<li>authToken: The Interactsh authentication token.</li>
 			</ul>
 		</li>
+	</ul>
 
 	<H2>See also</H2>
 	<table>