Seen in mozilla-mobile/fenix#18589

Currently on Android >=N && <=Q when users tap in app settings to set Firefox as the default browser we will open the system settings for from where they can do so.
To go one step further and highlight the actual setting they are expected to change we can use Intent extras as [shown here](https://github.com/duckduckgo/Android/blob/7c

Relevant spec sections:

https://drafts.csswg.org/selectors-4/#the-dir-pseudo
https://html.spec.whatwg.org/multipage/semantics-other.html#selector-ltr

The interesting cases to test are from the definition of "directionality" in HTML:
https://html.spec.whatwg.org/multipage/dom.html#the-directionality

• element with dir="ltr" matches :dir(ltr)
• root element without dir attr

Somehow we haven't written down exactly what the various events do.

We should take the opportunity to point people to DocLoad because that's what they will want 90% of the time.