Add more text formatting options on literature pages

[Jaeiya]

Right now, there's a very limited amount of Markdown features that are supported by the renderer; the reason for this is a focus on only what we needed at the time, but it's time to just expand the range for future use-cases.

Priority Features

• Headers 1 - 3

# Header 1
## Header 2
### Header 3

• Footnotes

Here's a simple footnote,[^1] and here's a longer one.[^bignote]

[^1]: This is the first footnote.

[^bignote]: Here's one with multiple paragraphs and code.

    Indent paragraphs to include them in the footnote.

    `{ my code }`

    Add as many paragraphs as you like.