Add remaining changes from AUTH48 review

[robUx4]

These includes formatting, (US) English errors, use of sections in references, etc.

This more or less matches the XML file sent with the AUTH48 review. There is some kind of formatting that doesn't seem possible to do with Markdown/mmark (usually in sub lists). mmark also adds a lot of where there is not in AUTH48.

This doesn't includes questions raised by the editor(s).

Some changes also impact the other Matroska CELLAR documents. We should regenerate them soon.

[robUx4]

@mbunkus @dericed if there's no objection I'll merge it this week-end. Then we can publish the other documents with the relevant changes (although we can't reference just RFC9559 yet).

[mbunkus]

Thanks for all your work, Steve, and sorry for not reacting sooner. Pretty busy. I do have reviewing thir PR on my TODO list for today or tomorrow. So please don't merge before Sunday. Thanks.

[robUx4]

No problem, there's no rush. Also we still have some reviewing steps before it's all finalized, at least the last call to make sure we agree on the final document. But I expect more steps to come, especially with the inconsistent backticking we use.

[JeromeMartinez]

@robUx4 @mbunkus Thank you both!