Automatically reload erlang_ls.config changes

[rlipscombe]

If I make any changes to erlang_ls.config, I have to either quit/reopen VS Code, or restart the extension host (which breaks other things). See https://erlangforums.com/t/can-i-reload-erlang-ls-config-without-restarting-vs-code/2074/3

It would be nice if the extension restarted itself or the server if the file changed.

[robertoaloi]

That makes sense. In the meantime, it should also be possible to Cmd-P and "reload window". We could also implement a "restart server" command (similar to what Rust Analyzer does) which simply restarts the server without affecting other extensions.

[rlipscombe]

Reload window seems to work. It's a bit slower than I'd like (and I'm not making it better by using VS Code Remote-SSH to home from the pub...). Something like Rust's "restart server" would work too.