Render mentions and other references properly

[drlef]

{actor} is not so helpful

[tofubert]

@drlef So I'm not sure how to render this nicely. my first thought as done in #83 was to fill in the text in the NCMessage, but that means we cant change style for the highlight there. So I'm inclined to do this in the Chat_Box, though I feel like this is getting to the point of pulling chat box lines into their own module :D.