Inventory of merged an pending PRs

I have been a bit lazy with the `awaits-merge` label. So need to figure out which of the proposals this year have already been merged.

There were also some historical once that are still not merged and we need to discuss what we do about those.

Review the repository's proposals and pull requests from this year, then identify historical proposals that remain unmerged. Record which proposals are merged or pending and summarize the unresolved historical cases; the inventory is done when all relevant proposals have been accounted for.

Written by the indexing model from the issue text.