Include HTML in docs markdown (fix alignment)

[Caellian]

@brndnmtthws I modified alignment documentation recently and accidentally broke it because pandoc removes embedded HTML - it's missing main table with alignments.

I tried fixing it in one of subsequent PRs but it didn't work. I'm not sure how to build documentation locally and can't preview changes in a PR which is why I created this issue. Can you try different options suggested in the following SO answer to see whether this can be fixed: Embed indented HTML in Markdown with Pandoc.

Allowing HTML would also enable much better documentation down the line.

[Caellian]

I decided to put in some time to understand where pandoc is used and how the website works, was pretty straightforward to apply suggestion then - even though I wasn't able to get headless tables to work because pandoc (MAN) and unified.js (web) don't support any common syntax extensions and HTML tables get removed from MAN.

Also figured out netlify bot posts a preview 🤦‍♂️ . I was just jumping over that bot comment out of habit.