gh-123445: calendar: Improve descriptions for day and month attributes (

GH-123483)

(cherry picked from commit 8447c93)

Co-authored-by: Mat S <mscull@gmail.com>
Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Co-authored-by: Eric V. Smith <ericvsmith@users.noreply.github.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Doc/library/calendar.rst

@@ -393,13 +393,22 @@ The :mod:`calendar` module exports the following data attributes:
 
 .. data:: day_name
 
-   An array that represents the days of the week in the current locale.
+   A sequence that represents the days of the week in the current locale,
+   where Monday is day number 0.
+
+       >>> import calendar
+       >>> list(calendar.day_name)
+       ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
 
 
 .. data:: day_abbr
 
-   An array that represents the abbreviated days of the week in the current locale.
+   A sequence that represents the abbreviated days of the week in the current locale,
+   where Mon is day number 0.
 
+       >>> import calendar
+       >>> list(calendar.day_abbr)
+       ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
 
 .. data:: MONDAY
           TUESDAY
@@ -426,17 +435,24 @@ The :mod:`calendar` module exports the following data attributes:
 
 .. data:: month_name
 
-   An array that represents the months of the year in the current locale.  This
+   A sequence that represents the months of the year in the current locale.  This
    follows normal convention of January being month number 1, so it has a length of
    13 and  ``month_name[0]`` is the empty string.
 
+       >>> import calendar
+       >>> list(calendar.month_name)
+       ['', 'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']
+
 
 .. data:: month_abbr
 
-   An array that represents the abbreviated months of the year in the current
+   A sequence that represents the abbreviated months of the year in the current
    locale.  This follows normal convention of January being month number 1, so it
    has a length of 13 and  ``month_abbr[0]`` is the empty string.
 
+       >>> import calendar
+       >>> list(calendar.month_abbr)
+       ['', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
 
 .. data:: JANUARY
           FEBRUARY