Update calendar.rst

Author: StanFromIreland

Doc/library/calendar.rst

@@ -399,12 +399,6 @@ For simple text calendars this module provides the following functions.
 
 The :mod:`calendar` module exports the following data attributes:
 
-.. data:: firstweekday
-   :no-index:
-
-   An :class:`int` (0-6) representing the current setting for the first weekday.
-   The default is 0, which corresponds to Monday.
-
 .. data:: day_name
 
    A sequence that represents the days of the week in the current locale,