Add docs for @aware directive

[calebporzio]

These are docs for the following PR: laravel/framework#39100

[calebporzio]

I struggled with the right code example for this. I landed on the simples example that wasn't overly contrived. The only tradeoff being that in a production app using purgeCSS, because we are dynamically generating the text- and bg- classes, they wouldn't get picked up.

I think the tradeoff here is worth it for demonstrating the technique.

[inxilpro]

You need to set the default in the parent and the child because @props doesn't get evaluated before the child has finished rendering. This may be something we want to consider before merging…

Suggested change

	@aware(['color'])
	@aware(['color' => 'gray'])

[taylorotwell]

Marking as draft until release day.