Add an `enableTagfilter` option to `HtmlRenderer` to eanble GFM `tagfilter` extension (dart-lang/markdown#447)

* Add GFM Disallowed Raw HTML support

* Fix errors caused by rebase.

* Update CHANGELOG.md
5 files changed
tree: 000b8ea87e6d4aed34c6c0d408baf3835d9b2c0a
  1. pkgs/