[libc++][ranges] Implement ranges::count{, _if}

Reviewed By: var-const, Mordante, ldionne, #libc

Spies: tcanens, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D121523

NOKEYCHECK=True
GitOrigin-RevId: 1306b1025c507ec8c406a975558007e3e94e5cbd
diff --git a/include/module.modulemap b/include/module.modulemap
index ef37387..cf74a07 100644
--- a/include/module.modulemap
+++ b/include/module.modulemap
@@ -294,6 +294,8 @@
       module pop_heap                 { private header "__algorithm/pop_heap.h" }
       module prev_permutation         { private header "__algorithm/prev_permutation.h" }
       module push_heap                { private header "__algorithm/push_heap.h" }
+      module ranges_count             { private header "__algorithm/ranges_count.h" }
+      module ranges_count_if          { private header "__algorithm/ranges_count_if.h" }
       module ranges_find              { private header "__algorithm/ranges_find.h" }
       module ranges_find_if           { private header "__algorithm/ranges_find_if.h" }
       module ranges_find_if_not       { private header "__algorithm/ranges_find_if_not.h" }