nonspec: Make requirements for draft reviews more explicit (#1201)

Currently CONTRIBUTING.md says that PRs that affect draft files have
'relaxed' approval requirements but does not specify what those relaxed
requirements are.

This PR makes the default requirements for draft PRs explicit (only 1
reviewer, no waiting period) in an attempt to speed progress on draft
changes. Approving reviewers will have the opportunity to indicate if
they want additional reviewers prior to submitting these draft PRs.

We will still have strict requirements (3 approvers, 72h waiting period)
when moving content from draft to rc or final status. This should allow
thorough review of changes in their finished state without hampering
progress on new tracks.

---------

Signed-off-by: Tom Hennen <[email protected]>

CONTRIBUTING.md

@@ -138,8 +138,12 @@ always requires one reviewer, even if the author has write access.
 
 Note 2: If the PR only touches files in the [Draft](docs/spec-stages.md)
 specification stage, then the "waiting period" and "# reviewers" are relaxed and
-up to Maintainer discretion. Files in the Draft stage have a large banner at the
-top of each rendered page, as well as the text "Status: Draft".
+up to Maintainer discretion (including the PR author if they're a maintainer). Note
+that a relaxed number of reviewers and waiting period may result in more back
+and forth with the expanded set of reviewers as drafts are finalized.
+Drafts should be indicated in the PR title following a pattern of `<type>: draft: <subject>`.
+Files in the Draft stage have a large banner at the top of each rendered page,
+as well as the text "Status: Draft".
 
 [squash and merge]: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/incorporating-changes-from-a-pull-request/about-pull-request-merges#squash-and-merge-your-commits