suggested extensions (#9526)

Follow-up from #9138

Release Notes:

- Adds suggested extensions for some filetypes
([#7096](https://github.com/zed-industries/zed/issues/7096)).

---------

Co-authored-by: Felix Zeller <felixazeller@gmail.com>

crates/language/src/language.rs

@@ -62,8 +62,8 @@ pub use buffer::Operation;
 pub use buffer::*;
 pub use diagnostic_set::DiagnosticEntry;
 pub use language_registry::{
-    LanguageQueries, LanguageRegistry, LanguageServerBinaryStatus, PendingLanguageServer,
-    QUERY_FILENAME_PREFIXES,
+    LanguageNotFound, LanguageQueries, LanguageRegistry, LanguageServerBinaryStatus,
+    PendingLanguageServer, QUERY_FILENAME_PREFIXES,
 };
 pub use lsp::LanguageServerId;
 pub use outline::{Outline, OutlineItem};

crates/language/src/language_registry.rs

@@ -85,6 +85,15 @@ enum AvailableGrammar {
     Unloaded(PathBuf),
 }
 
+#[derive(Debug)]
+pub struct LanguageNotFound;
+
+impl std::fmt::Display for LanguageNotFound {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "language not found")
+    }
+}
+
 pub const QUERY_FILENAME_PREFIXES: &[(
     &str,
     fn(&mut LanguageQueries) -> &mut Option<Cow<'static, str>>,
@@ -471,7 +480,7 @@ impl LanguageRegistry {
             .max_by_key(|e| e.1)
             .clone()
         else {
-            let _ = tx.send(Err(anyhow!("language not found")));
+            let _ = tx.send(Err(anyhow!(LanguageNotFound)));
             return rx;
         };