Dump(): React.JSX.Element
Renders /@:username/dumps/:slug, for anyone who may see the dump: a
private dump answers 404 to anyone but its poster. The dump comes from
GET /api/users/@:username/dumps/:slug, or from the navigation's state when
DumpEdit or a title edit here just saved it. Reached by a former name or
slug, the URL takes the current ones. Its comments, related dumps and
playlists come from their own endpoints once it is loaded, and the socket's
events keep them current; a reconnection fetches them and the dump again.
A dump deleted, or made private by its poster, while someone else views it
gives way to a notice. The poster and moderators can edit the title and the
note in place, and get a link to DumpEdit for the rest.