Reaction support

[rcurtin]

Hi there! Thanks so much for this bridge. It is an important part of my attempts to unify all the disparate chat services I have to use---without your work, I wouldn't be able to do that.

I've been playing with the bridge and it seems like the bridge doesn't support liking messages, or displaying when whoever I am chatting with has liked my message. Did I overlook some way to set this up? If it's not implemented, and you're looking for a little bit of help, I'd be happy to give it a shot, although I have no experience (...yet) with the internals of anything relating to Matrix.