Fix formatting of code blocks

[emlun]

Looks like the ``` syntax for code blocks isn't supported; use indentation by 4 spaces instead.

[ve7jtb]

You have made the lines too long. There is a 72 character max line length.
That is why I manually wrapped some of them to prevent them from being cut off or having to horizontally scroll for those blocks.

Remember the official versions are TEXT.

(969) Unused reference: There seems to be no reference to [hkdf] in the document
(1009) Unused reference: There seems to be no reference to [RFC3279] in the document
(333) Artwork too wide, reducing indentation from 3 to 0
(327) Section too wide, reducing indentation from 0 to 0
(359) Artwork too wide, reducing indentation from 3 to 0
(352) Section too wide, reducing indentation from 0 to 0
(401) Artwork too wide, reducing indentation from 3 to 0
(394) Section too wide, reducing indentation from 0 to 0
(142) Section too wide, reducing indentation from 0 to 0
(63) Section too wide, reducing indentation from 0 to 0
(60) Middle too wide, reducing indentation from 0 to 0
(333) Too long line found (L476), 5 characters longer than 72 characters:
(333) Too long line found (L477), 13 characters longer than 72 characters:
(333) Too long line found (L482), 6 characters longer than 72 characters:
(359) Too long line found (L511), 5 characters longer than 72 characters:
(359) Too long line found (L512), 13 characters longer than 72 characters:
(359) Too long line found (L514), 9 characters longer than 72 characters:
(359) Too long line found (L515), 25 characters longer than 72 characters:
(359) Too long line found (L516), 5 characters longer than 72 characters:
(401) Too long line found (L567), 5 characters longer than 72 characters:
(401) Too long line found (L568), 13 characters longer than 72 characters:
(401) Too long line found (L570), 9 characters longer than 72 characters:
(401) Too long line found (L571), 1 characters longer than 72 characters:
(401) Too long line found (L573), 5 characters longer than 72 characters:

[emlun]

Should be fixed now!

[emlun]

I've now also set up the GitHub Action to host rendered drafts on GitHub Pages: https://yubico.github.io/arkg-rfc/ , including preview and diff views of pull request branches.

[ve7jtb]

LGTM