Swift: Add missing '.'

Author: geoffw0

swift/ql/src/queries/Security/CWE-079/UnsafeWebViewFetch.qhelp

@@ -26,7 +26,7 @@
 <references>
 
 <li>
-  <a href="https://www.allysonomalley.com/2018/12/03/ios-bug-hunting-web-view-xss/">iOS Bug Hunting - Web View XSS</a>
+  <a href="https://www.allysonomalley.com/2018/12/03/ios-bug-hunting-web-view-xss/">iOS Bug Hunting - Web View XSS</a>.
 </li>
 
 </references>