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>

rust-toolchain.toml

@@ -1,5 +1,5 @@
 [toolchain]
-channel = "1.87"
+channel = "1.88"
 profile = "minimal"
 components = [ "rustfmt", "clippy" ]
 targets = [