Add font-display descriptor to improve performance

[david-poindexter]

Is your feature request related to a problem?

Currently, the font-display descriptor is not used in font-face at-rules. This should be used to improve performance metrics and to provide the user with a fallback font to be displayed while web fonts are being loaded. This is a recommended best practice.

Describe the solution you'd like

This should be used in accordance with this article. Using auto should suffice.

Describe alternatives you've considered

n/a

Additional context

n/a