Add heading classes

[ckconant]

Description

It would be helpful to add utility classes with each of the headings so that it is easy to style headings like others, while still allowing screen readers to read things properly. Essentially something like

h1, .h1 {}
h2, .h2 {}
h3, .h3 {}
...

Doing something like the above will allow developers to easily style a scenario such as

<h2 class="h6">This is some small text</h2>
<h3 class="h2">This is larger text</h3>
<p>lorem ipsum...</p>

Checklist

• I have read the CONTRIBUTING document.
• I have checked the issue tracker to make sure there isn’t already an open issue.