flags.xml: remove extra </dl> to allow clean builds
@@ -190,7 +190,7 @@ connections.</dd>
<code>1</code>, the cookie will have the <code>HttpOnly</code> flag set,
which means that the cookie is inaccessible to JavaScript code on
browsers that support this feature.</dd>
-</dl>
+
<dt>samesite</dt>
<dd>If set to anything other than <code>0</code>, the <code>SameSite</code>
attribute is set to the specified value. Typical values are <code>None</code>,
