Fix: Correctly nest `h-cite`s

As noticed in jvt.me#989, the rendering of Twitter -contexts has been broken when there are nested h-cites, as the child element does not have a separate h-cite, meaning a Microformats2 parser (i.e. for Bridgy) will pick up the child post, too, which leads to me to posting correctly to my site, but syndication interacts with the wrong content - which is bad!