zeta: Send up diagnostics with prediction requests (#24384)

This PR makes it so we send up the diagnostic groups as additional data
with the edit prediction request.

We're not yet making use of them, but we are recording them so we can
use them later (e.g., to train the model).

Release Notes:

- N/A

---------

Co-authored-by: Nathan <nathan@zed.dev>

crates/languages/src/lib.rs

@@ -2,7 +2,6 @@ use anyhow::Context as _;
 use gpui::{App, UpdateGlobal};
 use json::json_task_context;
 pub use language::*;
-use lsp::LanguageServerName;
 use node_runtime::NodeRuntime;
 use python::{PythonContextProvider, PythonToolchainProvider};
 use rust_embed::RustEmbed;