refactor: Better match rustc's internal renderer

Author: Muscraft

Cargo.lock

@@ -117,7 +117,10 @@ maintenance = { status = "actively-developed" }
 
 [dependencies]
 anstyle = "1.0.4"
+indexmap = "2.7.0"
+itertools = "0.13.0"
 memchr = { version = "2.7.4", optional = true }
+rustc-hash = "2.1.0"
 unicode-width = "0.2.0"
 
 [dev-dependencies]

Cargo.toml

@@ -41,7 +41,7 @@ fn simple() -> String {
     );
 
     let renderer = Renderer::plain();
-    let rendered = renderer.render(message).to_string();
+    let rendered = renderer.render(message);
     rendered
 }
 
@@ -79,7 +79,7 @@ fn fold(bencher: divan::Bencher<'_, '_>, context: usize) {
             );
 
             let renderer = Renderer::plain();
-            let rendered = renderer.render(message).to_string();
+            let rendered = renderer.render(message);
             rendered
         });
 }