chore: Bump Rust version to 1.88 (#33439)

Goodies in this version:
- if-let chains 🎉
- Better compiler perf for Zed
(https://github.com/rust-lang/rust/pull/138522)

For more, see: https://releases.rs/docs/1.88.0/

Release Notes:

- N/A

---------

Co-authored-by: Junkui Zhang <364772080@qq.com>

crates/project/src/lsp_store.rs

@@ -5743,7 +5743,10 @@ impl LspStore {
                 match language {
                     Some(language) => {
                         adapter
-                            .labels_for_completions(&[completion_item.clone()], language)
+                            .labels_for_completions(
+                                std::slice::from_ref(&completion_item),
+                                language,
+                            )
                             .await?
                     }
                     None => Vec::new(),