Previously only the first child node of a spoiler was considered to
determine if there should be a spoiler reason. This was, unfortunately,
incorrect, as soon as e.g. the reason had more than one space. This is
fixed by properly iterating all child nodes to search for the reason.
This PR adds support for nicer mentions in markdown: You can now
fetch the mention string of a user with `user.mention` which is
human-friendly (typically contains the display name), which will get
properly pillified upon passing through the markdown parser.
Sorunome
Christian Pauly
Nicolas Werner