chore: Clippy fixes for 1.80 (#13987)

The biggest hurdle turned out to be use of `Arc<Language>` in maps, as
`clippy::mutable_key_type` started triggering on it (due to - I suppose
- internal mutability on `HighlightMap`?). I switched over to using
`LanguageId` as the key type in some of the callsites, as that's what
`Language` uses anyways for it's hash/eq, though I've still had to
suppress the lint outside of language crate.

/cc @maxdeviant , le clippy guru.

Release Notes:

- N/A

crates/gpui/build.rs

@@ -7,7 +7,7 @@ use std::env;
 
 fn main() {
     let target = env::var("CARGO_CFG_TARGET_OS");
-
+    println!("cargo::rustc-check-cfg=cfg(gles)");
     match target.as_deref() {
         Ok("macos") => {
             #[cfg(target_os = "macos")]