<x-aura::heading level="1" size="display-lg">Display Large Heading</x-aura::heading>
<x-aura::heading level="1" size="xl">Level 1 Heading</x-aura::heading>
<x-aura::heading level="2" size="lg">Level 2 Heading</x-aura::heading>
<x-aura::heading level="3" size="md">Level 3 Heading</x-aura::heading>