Struts anchor tag doesn't support "disabled" even though docs indicate it does

Hello there,

When generating an anchor tag with the "disabled" attribute and the simple theme, struts does not seem to render it properly:

<%@taglib prefix="s" uri="/struts-tags" %>

...

<s:a action="myAction" cssClass="btn btn-default" disabled="true">
    <s:param name="myParam" value="#bean.Value"/>
    <s:text name="my.properties.key"/>
</s:a>

The generated link does not contain expected disabled="disabled".

The value is described in the TLD and is documented on the site https://struts.apache.org/tag-developers/a-tag :

    <attribute>
      <description><![CDATA[Set the html disabled attribute on rendered html element]]></description>
      <name>disabled</name>
      <required>false</required>
      <rtexprvalue>false</rtexprvalue>
    </attribute>

It looks like it's missing from the .ftl file? I added it manually as a work-around with an overridden template, but perhaps I missed something. We are admittedly on an old version of struts but I didn't see any differences in the current version of the git repo.

<#if parameters.disabled!false>
 disabled="disabled"<#rt/>
</#if>