I propose to remove the docs/architecture and docs/rfc directories from backport branches, and have these documents live only on master.

Rationale:

1. The copies on the backport branches are incomplete. They have only the docs that were present at the time we cut the branch.
2. The files on the backport branches get outdated. They don't have any revisions to the files they do contain since the time we cut the branch.

We would need to include a step in the release notes, as part of creating the backport branch, to remove those directories after the branch is cut. However, I think that would be worth a little extra work on those (rare) occasions to keep things simpler for ongoing maintenance.

• Remove from v0.35.x (Remove ADR and RFC docs from the v0.35.x backport branch. #7866)
• Remove from v0.34.x (Remove ADR and RFC docs from the v0.34.x backport branch. #7867)
• Remove from v0.33.x (Remove ADR docs from the v0.33.x backport branch. #7879)
• Update release instructions (Update release instructions for documentation. #7846)