Add todo

src/main.rs

@@ -268,7 +268,8 @@ fn diff_file(display_path: &str, lhs_path: &Path, rhs_path: &Path) -> DiffResult
 
     // TODO: take a Path directly instead.
     let path = Path::new(&display_path);
-    let ts_lang = guess(path).map(tsp::from_language);
+    // TODO: Prefer rhs_src if it's a new file.
+    let ts_lang = guess(path, &lhs_src).map(tsp::from_language);
 
     let arena = Arena::new();
     let (lang_name, lhs, rhs) = match ts_lang {