[libc++] Validates valid weekday indexed range.

[Mordante]

Summary

No code changes, but only increased the range in the tests.

Completes:

• LWG3273. Specify weekday_indexed to range of [0, 7]

[Mordante]

CI fixes

libcxx/docs/Status/Cxx20Issues.csv

 "`3235 <https://wg21.link/LWG3235>`__","``parse``\  manipulator without abbreviation is not callable","Belfast","",""
 "`3246 <https://wg21.link/LWG3246>`__","What are the constraints on the template parameter of ``basic_format_arg``\ ?","Belfast","","","|format|"
 "`3253 <https://wg21.link/LWG3253>`__","``basic_syncbuf::basic_syncbuf()``\  should not be explicit","Belfast","",""
 "`3245 <https://wg21.link/LWG3245>`__","Unnecessary restriction on ``'%p'``\  parse specifier","Belfast","","","|chrono|"
 "`3244 <https://wg21.link/LWG3244>`__","Constraints for ``Source``\  in |sect|\ [fs.path.req] insufficiently constrainty","Belfast","",""
 "`3241 <https://wg21.link/LWG3241>`__","``chrono-spec``\  grammar ambiguity in |sect|\ [time.format]","Belfast","|Complete|","16.0","|chrono| |format|"
 "`3257 <https://wg21.link/LWG3257>`__","Missing feature testing macro update from P0858","Belfast","",""
 "`3256 <https://wg21.link/LWG3256>`__","Feature testing macro for ``constexpr``\  algorithms","Belfast","|Complete|","13.0"
-"`3273 <https://wg21.link/LWG3273>`__","Specify ``weekday_indexed``\  to range of ``[0, 7]``\ ","Belfast","","","|chrono|"
+"`3273 <https://wg21.link/LWG3273>`__","Specify ``weekday_indexed``\  to range of ``[0, 7]``\ ","Belfast","|Complete|","16.0","|chrono|"
 "`3070 <https://wg21.link/LWG3070>`__","``path::lexically_relative``\  causes surprising results if a filename can also be a  *root-name*","Belfast","",""
 "`3266 <https://wg21.link/LWG3266>`__","``to_chars(bool)``\  should be deleted","Belfast","|Complete|","14.0"
 "`3272 <https://wg21.link/LWG3272>`__","``%I%p``\  should parse/format ``duration``\  since midnight","Belfast","","","|chrono| |format|"
 "`3259 <https://wg21.link/LWG3259>`__","The definition of *constexpr iterators* should be adjusted","Belfast","|Nothing To Do|","","|ranges|"
 "`3103 <https://wg21.link/LWG3103>`__","Errors in taking subview of ``span``\  should be ill-formed where possible","Belfast","",""
 "`3274 <https://wg21.link/LWG3274>`__","Missing feature test macro for ``<span>``\ ","Belfast","|Complete|","11.0"
 "`3276 <https://wg21.link/LWG3276>`__","Class ``split_view::outer_iterator::value_type``\  should inherit from ``view_interface``\ ","Belfast","|Complete|","15.0","|ranges|"
 "`3277 <https://wg21.link/LWG3277>`__","Pre-increment on prvalues is not a requirement of ``weakly_incrementable``\ ","Belfast","|Nothing To Do|","","|ranges|"

libcxx/test/std/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/index.pass.cpp

int main(int, char**)
     using weekday         = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
 
     ASSERT_NOEXCEPT(                    std::declval<const weekday_indexed>().index());
     ASSERT_SAME_TYPE(unsigned, decltype(std::declval<const weekday_indexed>().index()));
 
     static_assert( weekday_indexed{}.index() == 0, "");
 
-    for (unsigned i = 1; i <= 5; ++i)
+    // This is the valid range of values defined in [time.cal.wdidx.members]/1.
+    for (unsigned i = 0; i <= 7; ++i)
     {
         weekday_indexed wdi(weekday{2}, i);
         assert( static_cast<unsigned>(wdi.index()) == i);
     }
 
   return 0;
 }