message: Document new behaviour of expr_linearization
diff: @@ -182,6 +182,9 @@ pub fn linearization_columns<F: FftField + SquareRootField>(
  /// Linearize the `expr`.
  ///
  +/// If the `feature_flags` argument is `None`, this will generate an expression using the
  +/// `Expr::EnabledIf` variant for each of the flags.
  +///
  /// # Panics
  ///
  /// Will panic if the `linearization` process fails.
  