Remove incorrect use of `p-name` on non-articles
As raised by aaronpk on the IndieWeb-dev chat, using the p-name
here
is not correct, as it should be only used for the title of a post. In
these cases, these content types do not have a title (as that is
reserved for articles), just content.
This will screw with post-type-discovery, as that will return article
when it finds a p-name
.
In the case of RSVPs, we can remove the p-name
completely, as it was
meant to be hidden metadata, which now no longer makes sense.
Closes #894 (closed).