reword the comment

Author: darren

services/auth/source/smtp/source_authenticate.go

@@ -41,10 +41,10 @@ func (source *Source) Authenticate(ctx context.Context, user *user_model.User, u
 	}
 
 	if err := Authenticate(auth, source); err != nil {
-		// when authentication via smtp fails, wrap the error as ErrInvalidArgument
-		// with the original textproto.Erro as the cause
+		// when authentication via smtp fails, wraps ErrInvalidArgument
+		// with the original textproto.Error as the cause,
 		// so it will show username or password to the user
-		// while log the original error so that admin can check the actual reason
+		// while log the original error so that admin can check.
 		// see: routers/web/auth/auth.go SiginPost
 		if tperr, ok := err.(*textproto.Error); ok {
 			return nil, errors.Join(util.ErrInvalidArgument, tperr)