Rework key_colnames

[brookslogan]

Checklist

Please:

• Make sure this PR is against "dev", not "main" (unless this is a release
  PR).
• Request a review from one of the current main reviewers:
  brookslogan, nmdefries.
• Makes sure to bump the version number in DESCRIPTION. Always increment
  the patch version number (the third number), unless you are making a
  release PR from dev to main, in which case increment the minor version
  number (the second number).
• Describe changes made in NEWS.md, making sure breaking changes
  (backwards-incompatible changes to the documented interface) are noted.
  Collect the changes under the next release number (e.g. if you are on
  1.7.2, then write your changes under the 1.8 heading).
• See DEVELOPMENT.md for more information on the development
  process.

Change explanations for reviewer

• Make key_colnames.epi_archive output its unique key colnames (including version).
• Make key_colnames.data.frame require other_keys to be passed.
• Remove key_colnames.default.
• Require exclude = to be passed by name in key_colnames.
• Require dots to be empty in key_colnames.
  • Note: this triggers some errors in epipredict tests. See below.

epipredict errors

Originally, I misread and thought these were from passing other_keys = hopefully-redundantly into key_colnames.epi_df and having them be ignored. I was planning to do something like

  expected_other_keys <- attr(x, "metadata")$other_keys
  if (is.null(other_keys)) {
    other_keys <- expected_other_keys
  } else {
    if (!identical(other_keys, expected_other_keys)) {
      cli_abort(c(
        "`other_keys` was provided, but didn't match expectations from inspecting `x`",
        "*" = "`other_keys` was {format_chr_with_quotes(other_keys)}",
        "*" = "`expected_other_keys` was {format_chr_with_quotes(expected_other_keys)}",
        "i" = "If you resolve this discrepancy by adjusting the metadata of `x`, you
               shouldn't have to pass `other_keys =` here anymore unless you want to
               continue to perform this check."
      ))
    }
  }

However, the error is actually from passing extra_keys = (which was also previously ignored, but it sounds like it has a different meaning). I am looking a bit more into this.

• todo: decide what to do re. extra_keys =
  • idea for now: forbid + PR to epipredict to specify other_keys = instead. If current behavior of other_keys = with epi_dfs breaks later, then decide whether to change things here or adjust any offending steps/layers.
• todo: check whether epipredict#410 is caught... requiring other_keys = in key_colnames.data.frame should be flagging this, right?
  • It is. Also need to include fix in epipredict PR before merging this.
• todo: prepare epipredict PR and get it merged

Magic GitHub syntax to mark associated Issue(s) as resolved when this is merged into the default branch

• Resolves key_colnames returns wrong values for archive data #565

[brookslogan]

• don't actually merge this into current target branch; target branch is just for a more limited diff. Let Fix age group rate aggregation example #591 merge into dev first. then either
  • change base to dev, get Update revision_summary #540 merged into this, combine titles & changelog
  • change base to lcb/key_colnames-revision_summary-age_agg-updates and open PR here to hold combined changelog (although it shouldn't actually list the age agg updates)