Kill LSP gracefully

[dead10ck]

https://github.com/helix-editor/helix/blob/master/helix-lsp/src/client.rs#L62

It seems kill_on_drop sends a SIGKILL which is kind of aggressive, and could cause corruption. It's occurring to me that this may be why rust-analyzer has to reindex everything every time it runs. It also looks like there isn't a way to send a SIGTERM through the built-in tokio API. It looks like we'd have to add platform-specific code to handle this properly.

Originally posted by @dead10ck in #3435 (comment)

[mangas]

https://docs.rs/nix/latest/nix/ may have some useful stuff for this

[pascalkuthe]

Pretty sure this is fixed now wooth us giving lsps a ti.eout to close before force closing them

[dead10ck]

Are LS's supposed to terminate themselves? Or is it common to have to send them a SIGTERM?

[pascalkuthe]

There is a multiphase shutdown but in the end they are supposed to do it kn their own https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#exit

I think we have a timeout that waits for them to shutdown if they don't we kill