Create documentation guidelines

[kianenigma]

Main tasks:

• [x] General Rust code guides: https://hackmd.io/@kizi/S1xDsGWE2
• [x] https://github.com/paritytech/substrate/issues/13299: https://hackmd.io/4pjRqPNNTnGXJHKK9jv90A

[hummusonrails]

I'm "assigning" this to @aaronbassett to help think through as the FRAME developer pathway expert in our team. I'm also assigning it to myself as someone who's done a lot on docs in general, even though not FRAME specifically.

[hummusonrails]

What do we want the final output of this to be? A markdown doc outlining the guidelines for writing FRAME docs -- the things that they ought to have, must have, and ought not and must not have?

[kianenigma]

What do we want the final output of this to be? A markdown doc outlining the guidelines for writing FRAME docs -- the things that they ought to have, must have, and ought not and must not have?

Correct. a few pieces:

1. General documentation guide-lines.
2. A rough template of how to apply that to FRAME pallets, because they are so important.
3. We put this somewhere in the how to contribute guide.
4. We put this in the PR template that @sacha-l is building
5. This will be our yardstick when policing other PRs :D

I am writing initial versions of all of the above; feel free to comment.

[sacha-l]

My suggestions for a new PR template: https://github.com/paritytech/substrate/pull/14148