Reorganize Spec for consistency and clarity

[Ethan-Arrowood]

While attempting to fix the problems detailed in #5 I realized that there was a lot of inconsistencies between the usage of markdown and html. Furthermore, the linking was so difficult for me to fix.

This PR is a rewrite/reorganization of the spec that follows patterns I see in the Streams and Fetch specs. It strictly uses HTML elements instead of markdown. It also attempts to reorganize the information in such a way that allows for easier linking, and ideally improved readability.

Still some minor things to fix up. But wanted to share so we can start reviewing asap.

🚀

[Ethan-Arrowood]

Thank you for the review! I'm going to merge this now and then we can iterate on some of the other pieces in follow up PRs.

Things to revisit:

• remove concept section
• enforce line length with some sort of tooling (if at all possible)
• https://github.com/wintercg/proposal-sockets-api/pull/8/#discussion_r1318757521 (state that the socket should be returned in a pending state rather than connected)
• https://github.com/wintercg/proposal-sockets-api/pull/8/#discussion_r1318762226 (should we define a constructor for the Socket class)