Sanitize language server diagnostics coming from Rust

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

crates/zed/src/language.rs

@@ -1,4 +1,6 @@
 pub use language::*;
+use lazy_static::lazy_static;
+use regex::Regex;
 use rust_embed::RustEmbed;
 use std::borrow::Cow;
 use std::{str, sync::Arc};
@@ -7,6 +9,30 @@ use std::{str, sync::Arc};
 #[folder = "languages"]
 struct LanguageDir;
 
+struct RustDiagnosticProcessor;
+
+impl DiagnosticProcessor for RustDiagnosticProcessor {
+    fn process_diagnostics(&self, params: &mut lsp::PublishDiagnosticsParams) {
+        lazy_static! {
+            static ref REGEX: Regex = Regex::new("(?m)`([^`]+)\n`").unwrap();
+        }
+
+        for diagnostic in &mut params.diagnostics {
+            for message in diagnostic
+                .related_information
+                .iter_mut()
+                .flatten()
+                .map(|info| &mut info.message)
+                .chain([&mut diagnostic.message])
+            {
+                if let Cow::Owned(sanitized) = REGEX.replace_all(message, "`$1`") {
+                    *message = sanitized;
+                }
+            }
+        }
+    }
+}
+
 pub fn build_language_registry() -> LanguageRegistry {
     let mut languages = LanguageRegistry::default();
     languages.add(Arc::new(rust()));
@@ -26,6 +52,7 @@ fn rust() -> Language {
         .unwrap()
         .with_outline_query(load_query("rust/outline.scm").as_ref())
         .unwrap()
+        .with_diagnostics_processor(RustDiagnosticProcessor)
 }
 
 fn markdown() -> Language {