build: support `lint-md-fix`
Similar to lint-js-fix, this PR adds submit for lint-md-fix, which supplies the --fix CLI argument to the Markdown linter.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Similar to lint-js-fix, this PR adds submit for lint-md-fix, which supplies the --fix CLI argument to the Markdown linter.