fix(error): normalize whitespace during msg_to_buffer

compiler/rustc_errors/src/emitter.rs

@@ -1336,6 +1336,7 @@ impl EmitterWriter {
         //                see?
         for (text, style) in msg.iter() {
             let text = self.translate_message(text, args).map_err(Report::new).unwrap();
+            let text = &normalize_whitespace(&text);
             let lines = text.split('\n').collect::<Vec<_>>();
             if lines.len() > 1 {
                 for (i, line) in lines.iter().enumerate() {