Document default for [weekday]

diagrams/diagrams.py

@@ -55,7 +55,7 @@ def __init__(self, name, diagram):
     0, '1+', '1', '2', '3', '4', '5', '6', '7', '8', '9'))
 weekday_repr = Sequence('repr:', Choice(
     0, 'long', 'short', 'sunday', 'monday'))
-weekday_one_indexed = Sequence('one_indexed:', Choice(0, 'false', 'true'))
+weekday_one_indexed = Sequence('one_indexed:', Choice(0, 'true', 'false'))
 week_number_repr = Sequence('repr:', Choice(0, 'iso', 'sunday', 'monday'))
 year_repr = Sequence('repr:', Choice(0, 'full', 'last_two'))
 year_base = Sequence('base:', Choice(0, 'calendar', 'iso_week'))

src/api/format-description.md

@@ -301,7 +301,7 @@ ASCII whitespace characters.
   the weekday's full name in English, while the short is the first three letters. There are also
   _sunday_ and _monday_ representations, which are numerical. These formats are either zero to six
   or one to seven (depending on whether `one_indexed` is false or true, respectively), with the
-  named day being at the start of that range.
+  named day being at the start of that range. The default for `one_indexed` is true.
 
   When parsing, there is the option to consume text-based formats case-insensitively.