Support exit notification

[etherbob]

Per a report from another user who tested out building and running fuzzy_rubby_server standalone:

I could manage to build and install the LSP by:
git clone the project
cd to the project directory
build the executable : cargo build --release --target=aarch64-apple-darwin
symlink the .../fuzzy_ruby_server/bin/fuzzy_darwin-arm64 binary into the standard bin/. directory
configure BBEdit to use this binary for the ruby language
The LSP seems to be working as expected and logged in the LanguageServerProtocol-Ruby.txt file.
But there is a caveat: BBEdit will freeze when quitting, probably due to the LSP not behaving as expected when asked to shutdown.
I suspect the LSP does not respond to the Exit Notification.
{"jsonrpc":"2.0","id":2,"method":"shutdown"}Content-Length: 38

{"jsonrpc":"2.0","result":null,"id":2}Content-Length: 33

{"jsonrpc":"2.0","method":"exit"} ...
If this is indeed the cause, it should be reported to the developer.

With the disclaimer that I've not done anything in rust before, but I didn't see anything in the server to handle "exit" requests. I also couldn't tell for certain if TowerLSP is supposed to handle exit requests without any additional implementation.

[etherbob]

Ahh, might indeed be a TowerLSP issue.

[pheen]

It should be responding to shutdown requests. As a backup, Fuzzy grabs the editor process and watches it and will automatically shut down when the editor process is no longer available. https://github.com/pheen/fuzzy_ruby_server/blob/master/src/main.rs#L42-L58

[etherbob]

@pheen I might be misundersatnding but per ebkalderon/tower-lsp#399 and reports from other users it is not responding to exit requests and the editor itself is hanging waiting for the server to exit.