message: fix out-of-date reference to ContiguousRange::element_t
diff: @@ -326,13 +326,13 @@ namespace ranges
  requires ContiguousRange<Rng>() &&
  True<range_cardinality<Rng>::value < cardinality{}>())()
  span(Rng &&rng) ->
  - span<concepts::ContiguousRange::element_t<Rng>>;
  + span<detail::element_t<Rng>>;
  CONCEPT_template(typename Rng)(
  requires ContiguousRange<Rng>() &&
  True<range_cardinality<Rng>::value >= cardinality{}>())()
  span(Rng &&rng) ->
  - span<concepts::ContiguousRange::element_t<Rng>,
  + span<detail::element_t<Rng>,
  static_cast<detail::span_index_t>(range_cardinality<Rng>::value)>;
  #endif
  