Where is the tasklist extension?
================================
At the moment (`0.27.1.gfm.0`), the `tasklist` extension does not show up in `--list-extensions`; its test case in `test/spec.txt` is disabled; and it doesn't seem to be mentioned anywhere else in the code base. Am I right it's not included in the code base? Any plan to release it?
cmark-gfm 0.27.1.gfm.0 (new formula)
====================================
- [x] Have you followed the [guidelines for contributing](https://github.com/Homebrew/homebrew-core/blob/master/CONTRIBUTING.md)?
- [x] Have you checked that there aren't other open [pull requests](https://github.com/Homebrew/homebrew-core/pulls) for the same formula update/change?
- [x] Have you built your formula locally with `brew install --build-from-source <formula>`, where `<formula>` is the name of the formula you're submitting?
- [x] Does your build pass `brew audit --strict <formula>` (after doing `brew install <formula>`)?
-----
Official C implementation of GFM, forked from cmark (expect the "not canonical repository" audit error).