Commits
David Li authored and Antoine Pitrou committed d77e272c81d
ARROW-12950: [C++] Add count_substring kernel Depends on ARROW-12969. ignore_case is not included here; I'll include it with the regex variant in ARROW-12952. Closes #10454 from lidavidm/arrow-12950 Authored-by: David Li <li.davidm96@gmail.com> Signed-off-by: Antoine Pitrou <antoine@python.org>