SPA: BrManageContentButton will not render without documentTemplateQuery parameter

This might be by design, but we should document it. At the moment, something like this will not render a button:

<BrManageContentButton parameter="document" content=

{document} />

this works:

<BrManageContentButton documentTemplateQuery="new-news-document" content={document}

/>

It seems that documentTemplateQuery is a required parameter, and we should at least document it as such (if that is the case).