Fix typo add missing href, and remove stray code fence

[pavlenex]

This PR fixes a small typo and fix references in protocol security by add missing href and remove stray code fence ```.

I will be sending several small PR typo fixes in this repo, as part of the new website PR stratum-mining/stratumprotocol.org#300

The new website, just like the current one uses sv2-specs repo as a submodule, and whenever there's a marge in this repo, it SHOULD trigger a workflow which updates the submodule and rebuilds the website, so we always have stratumprotocol.com/specification page 1:1 as sv2-specs repo.

I'll be making several smaller PR's so we can test if workflows work good, will give green light when these are good to go one by one.

[plebhash]

@pavlenex we try to avoid introducing "merge" commits as means to keep PRs up-to-date

could you do the following steps?

• drop fcb7f87 from your branch
• rebase your branch against main

that will put all your commits on top of main's HEAD