fix: corrected spelling

[TimeTravelPenguin]

Corrected spelling in the manual and in src comments

[tingerrr]

Thank you!

[TimeTravelPenguin]

Thank you!

No problem. In one of the Typst repos, they mention using a tool called Typos. I just gave it a run once I spotted two of them on my own.

It is definitely worth adding to your CI and/or IDE's LSP.

[tingerrr]

I'm not sure if CI should fail because of a typo, I guess if @JamesxX wants to add it he can, I'm indifferent about it.

[TimeTravelPenguin]

To be fair, I only use it in my pre-commits. Doing anything like GH Actions is a pain unless it's a decently sized process, or if you prefer it.