The attempt to log a warning in case a hst component has a pointless renderer does not work properly

The problem is as follows:

The HST tries to log a warning when there is a hst component with a jsp, but the parent component does not have a <hst:include> for that component and the renderer does not add any head contributions.

Problem is only that headElements are stored on the root responseState, so childResponse.getHeadElements() will never contain headElements. We could of course keep track of a boolean flag that indicates that a response has added headElements to a parent, but with hindsight I don't think the game is worth the candle.

Another thing that would incorrectly log a warning, is if the renderer would be something like

<#if title??>
<@hst.headContribution keyHint="hst.seo.document.title">
<title>${title?xml}</title>
</@hst.headContribution>
</#if>

and the title would be null. Then, there is no head contribution added. The HST cannot know whether this is waste or not. We can only remove the warning