message: elle.Option: Improve documentation.
diff: @@ -58,9 +58,10 @@ namespace elle
  using Self = Option<Types ...>;
  using Super = _details::OptionHelper<0u, 0u, 0, Types ...>;
  using Super::Super;
  - /// Create an Option.
  + /// Move-construct an Option<Types...> initialized from an rvalue-ref to
  + /// 'value' of type 'T'.
  ///
  - /// @tparam T A type.
  + /// @tparam T The type of the given value, that must be part of Types.
  /// @param value An r-value reference.
  template <typename T>
  Option(T&& value);
  