Responsive Display Headings

Created by: sunyang713

I really like these larger, thinner headings that are provided:

<h1 class="display-1">Display 1</h1>
<h1 class="display-2">Display 2</h1>
<h1 class="display-3">Display 3</h1>
<h1 class="display-4">Display 4</h1>

As shown here: https://v4-alpha.getbootstrap.com/content/typography/#display-headings

But I've find that on smaller screens, these are almost always way too large. Could you consider adding responsive breakpoints like so:

<h1 class="display-l-1">Display 1</h1>
<h1 class="display-l-2">Display 2</h1>
<h1 class="display-md-3">Display 3</h1>
<h1 class="display-md-4">Display 4</h1>

so that the text can return to the standard h1 h2 etc font style on smaller screens?