Migrate the existing checker / suggester code to instead use the new validator framework. We need to add,
- An insertable regex validator that matches variables like: %s, %2$s, %.2f
- Insertables for HTML tag
We'll need to update the YAML configuration file located here - https://phabricator.wikimedia.org/diffusion/GTWN/browse/master/groups/
Documentation: https://www.mediawiki.org/wiki/Help:Extension:Translate/Validators
Example patch: https://gerrit.wikimedia.org/r/c/translatewiki/+/550918