Vibe check: edition cadence changes

The edition team has been discussing whether to adjust the edition cadence and process. We're expecting to post an RFC for full discussion, but are looking to get initial vibe checks from interested teams, starting with T-lang and T-cargo (though we're happy to get input from anyone).

At a high level the goals of making changes are to:

• Decrease the burden on T-edition and other relevant teams by spreading out edition proposals, rather than concentrating them in a particular calendar year
• Reduce wait times for features that can ship now if we can tweak them in a subsequent edition that's "soon", rather than years away.

The current concrete proposal -- though we are not tied to any particular aspect of it -- is to:

• Merge proposals into the next edition continuously
  • Documentation, testing, etc. happen prior to FCP merge.
• Allow any release to be an edition

The "core experience" of editions that we've established in 2021/2024 does not change: automated migrations are still expected, editions remain opt-in, etc.

For a more complete elaboration see our current draft here. Right now we're looking to get input on:

• What needs from your team should we keep in mind for iterating on how we do editions?
• What are you worried about with changes here?
• Any other opinions people have to offer.