message: Remove the iter_impl<const basic_json> copy constructor and copy assignment
diff: @@ -8054,9 +8054,10 @@ class basic_json
  }
  /*!
  - @note The conventional copy constructor is not defined. It is replaced
  - by either of the following two converting constructors.
  - They support copy from iterator to iterator,
  + @note The conventional copy constructor and copy assignment are
  + implicitly defined.
  + Combined with the following converting constructor and assigment,
  + they support: copy from iterator to iterator,
  copy from const iterator to const iterator,
  and conversion from iterator to const iterator.
  However conversion from const iterator to iterator is not defined.
  @@ -8072,16 +8073,7 @@ class basic_json
  {}
  /*!
  - @brief converting constructor
  - @param[in] other const iterator to copy from
  - @note It is not checked whether @a other is initialized.
  - */
  - iter_impl<const basic_json>(const iter_impl<const basic_json>& other) noexcept
  - : m_object(other.m_object), m_it(other.m_it)
  - {}
  -
  - /*!
  - @brief copy assignment
  + @brief converting assignment
  @param[in,out] other non-const iterator to copy from
  @return const/non-const iterator
  @note It is not checked whether @a other is initialized.
  @@ -8098,24 +8090,6 @@ class basic_json
  return *this;
  }
  - /*!
  - @brief copy assignment
  - @param[in,out] other const iterator to copy from
  - @return const iterator
  - @note It is not checked whether @a other is initialized.
  - */
  - iter_impl<const basic_json>& operator=(iter_impl<const basic_json> other) noexcept(
  - std::is_nothrow_move_constructible<pointer>::value and
  - std::is_nothrow_move_assignable<pointer>::value and
  - std::is_nothrow_move_constructible<struct internal_iterator>::value and
  - std::is_nothrow_move_assignable<struct internal_iterator>::value
  - )
  - {
  - std::swap(m_object, other.m_object);
  - std::swap(m_it, other.m_it);
  - return *this;
  - }
  -
  private:
  /*!
  @brief set the iterator to the first value
  