feat: Add LSP stub

[vanillajonathan]

Adds a stub implementations of a basic Language Server Protocol (LSP) to prqlc. LSP clients can connect to it and disconnect from it.

It use the lsp-server crate used by the official rust-analyzer.

The LSP specification is at https://microsoft.github.io/language-server-protocol/specifications/specification-current

[max-sixty]

looks cool, would be great to build this out in time!

to reduce dependencies in there meantime, could we add an optional lsp feature?

[vanillajonathan]

Okay, I made the dependency optional.

Yes it would be cool build this out in time. The next steps we need to do is to create match statements for DidOpenTextDocument, DidChangeTextDocument and DidCloseTextDocument then proceed with Completion, Formatting and HoverRequest.

[max-sixty]

Looks good! May need some refining on the tests outputs but good to go otherwise

[vanillajonathan]

I think no more tests are needed for now because we shouldn't test the lsp-server crate. We can add more tests later when we add more handlers such as DidOpenTextDocument, DidChangeTextDocument and DidCloseTextDocument.

The test fails on some test-deps-min-version (verify Rust minimum version) thing.

Can you merge this?

[max-sixty]

The test fails on some test-deps-min-version (verify Rust minimum version) thing.

OK, but we can't have main failing, so we need to fix that...

It seems to additionally be failing because the completion snapshot files need updating: https://github.com/PRQL/prql/actions/runs/14046209187/job/39327515449?pr=5197

[vanillajonathan]

Okay, I updated shell completion snapshots.

[max-sixty]

but lsp shouldn't be in cli by default, then we're including features that introduce dependencies without any functionality

does that make sense? I think you can recognize this!

[max-sixty]

(it's possible that fixing this undoes the changes to the tests, apologies if so — they should all reset with the standard test commands at least)

[vanillajonathan]

Yeah, that makes sense.

[max-sixty]

lgtm!