Prototype USWDS subcomponent scan

[gbinal]

• Presence of 'Here's how you know' link as seen in the banners of epa.gov and gsa.gov, whereas cancer.gov is an example of one that doesn't.

Ideas for how to do it:

• Look for <span class="usa-banner__button-text">Here’s how you know</span>, or
• >Here's how you know<, or
• Look for usa-banner_button-text

If a new field, perhaps we call it uswds_subcomponent