fix(pycharm-banner): Provide visual cue by underlining link

[CuriousLearner]

Underline to get PyCharm for 30% off to indicate it's a link.

[bmispelon]

Thanks for working on this!

This looks good visually, but the original ask was that the whole text stays a link, and to either underline the "get PyCharm for 30% off" only, or if not possible then the whole text.

[CuriousLearner]

Underlining the get PyCharm for 30% off:

On hover default state underlines the whole banner:

It looks a little odd; we may remove the underline on the hover state if there is a preference.

[adamzap]

@CuriousLearner Should we close this since #2299 was merged?

[CuriousLearner]

Sure, thanks everyone!