Use @tailwindcss/typography for About page too

[jhannah-netlify]

class "prose" comes from https://tailwindcss.com/docs/plugins#typography

And that's what's used in post bodies.

When we look at the table styling preview as documented by those developers

https://play.tailwindcss.com/uj1vGACRJA?layout=preview

We see that this is the way they want tables to look.

So let's also use that for pages other than post pages for consistency.

Fixes #18