[Disco]: recommending on{event} instead of on-modifier

Motivation: https://github.com/krausest/js-framework-benchmark/pull/1608

> It's idiomatic to use `{{on}}` for event listening, and `{{on}}` is the only way to have _conditionally applied_ / dynamic event listeners, but for performance sensitive situations, we can _do less_ by using the platform, and we don't need any cleanup behavior, so native `onclick` should be sufficient.