Add overload `std.algorithm.sorting.schwartzSort!(alias transform, SwapStrategy ss, R)`

$(REF schwartzSort, std,algorithm,sorting) now has an overloaded version that can be
used to provide a `SwapStrategy` without also explicitly specifying the predicate to
sort by.

-------
auto s1 = a.schwartzSort!(abs, SwapStrategy.stable);

// The old syntax still works.
auto s2 = a.schwartzSort!(abs, "a < b", SwapStrategy.stable);
-------
