Fix links on the news grid cards

[demi-johnson]

The USWDS link component guidance states:
Don’t rely on color alone to distinguish links. Site visitors should be able to distinguish text links from surrounding text. In most cases, include an underline or bottom border on text links, in addition to a consistent link color. Text links not distinguished with an underline need a contrast level of at least 3:1 with their surrounding text (the same as AA Large, or a USWDS magic number of 40) and should show an underline on hover.

In the latest edition of the News Grid template, I removed the underline from the text link because I didn't like the visual look of underlined text on a card. How can show an underline on hover?