libstdc++: Adding missing feature-test macros for C++23 ranges algos
This patch also renames __cpp_lib_fold to __cpp_lib_ranges_fold
as per the current draft standard.
libstdc++-v3/ChangeLog:
* include/bits/ranges_algo.h (__cpp_lib_ranges_contains):
Define for C++23.
(__cpp_lib_ranges_iota): Likewise.
(__cpp_lib_ranges_find_last): Likewise.
(__cpp_lib_fold): Rename to ...
(__cpp_lib_ranges_fold): ... this.
* include/std/version: As above.
* testsuite/25_algorithms/fold_left/1.cc: Adjust after
renaming __cpp_lib_fold.
* testsuite/std/ranges/version_c++23.cc: Verify values
of the above feature-test macros.
(cherry picked from commit
95525c5b8c2d6317b693d441520b7bc808cf9ec7)