- for all algorithms taking more than one range, add a `robust` test to
check the case where the ranges have different value types and the
given projections are different, with each projection applying to
a different value type;
- fix `ranges::include` to apply the correct projection to each range.
Differential Revision: https://reviews.llvm.org/D130515
- create the headers (but not include them from `<algorithm>`);
- define the niebloid and its member functions with the right signatures
(as no-ops);
- make sure all the right headers are included that are required by each
algorithm's signature;
- update `CMakeLists.txt` and the module map;
- create the test files with the appropriate synopses.
The synopsis in `<algorithm>` is deliberately not updated because that
could be taken as a readiness signal. The new headers aren't included
from `<algorithm>` for the same reason.
Differential Revision: https://reviews.llvm.org/D129549
