What does this PR change? What problem does it solve?

Markdownify the author string so that we can use email, github, or site section links for authors more easily.

Was the change discussed in an issue or in the Discussions before?

I did approximately 1 second of searching and didn't see this, but this is a standard feature in other hugo themes so I thought I'd suggest it here

PR Checklist

• I have enabled maintainer edits for this PR.
• I have verified that the code works as described/as intended.
  • I checked this with one author and multiple authors and both scenarios work.
• This change does not include any CDN resources/links.
• This change does not include any unrelated scripts such as bash and python scripts.