Timeouts

[KillTheMule]

... were removed when asyncifying.

Do we need them? Note that if neovim closes unexpectedly, the channel will be closed and all pending requests get sent an error, so we will not hang indefinitely.

Plus https://docs.rs/tokio/0.2.4/tokio/time/fn.timeout.html is a thing, so clients could at least theoretically just add it themselves.