Converting fns to generics to make them extendable

[ddsjoberg]

What changes are proposed in this pull request?

• Converting ard_*() functions and other helpers to S3 generics to make them extendable. (Make ard_categorical() and friends generics? #227)

Reference GitHub issue associated with pull request. e.g., 'closes #'
closes #227

---

Pre-review Checklist (if item does not apply, mark is as complete)

• All GitHub Action workflows pass with a ✅
• PR branch has pulled the most recent updates from master branch: usethis::pr_merge_main()
• If a bug was fixed, a unit test was added.
• Code coverage is suitable for any new functions/features (generally, 100% coverage for new code): devtools::test_coverage()
• Request a reviewer

Reviewer Checklist (if item does not apply, mark is as complete)

• If a bug was fixed, a unit test was added.
• Run pkgdown::build_site(). Check the R console for errors, and review the rendered website.
• Code coverage is suitable for any new functions/features: devtools::test_coverage()

When the branch is ready to be merged:

• Update NEWS.md with the changes from this pull request under the heading "# cards (development version)". If there is an issue associated with the pull request, reference it in parentheses at the end update (see NEWS.md for examples).
• All GitHub Action workflows pass with a ✅
• Approve Pull Request
• Merge the PR. Please use "Squash and merge" or "Rebase and merge".

[github-actions]

Code Coverage Summary

Filename                       Stmts    Miss  Cover    Missing
---------------------------  -------  ------  -------  -------------------------------
R/apply_fmt_fn.R                  83      16  80.72%   97-104, 186-193
R/ard_attributes.R                32       0  100.00%
R/ard_categorical.R              348      17  95.11%   123, 223, 383-384, 540-555, 589
R/ard_complex.R                   34       0  100.00%
R/ard_continuous.R               176       4  97.73%   118, 200-201, 299
R/ard_dichotomous.R               66       2  96.97%   60, 146
R/ard_hierarchical.R              83       0  100.00%
R/ard_missing.R                   21       0  100.00%
R/ard_stack.R                     60       0  100.00%
R/as_nested_list.R                41       0  100.00%
R/bind_ard.R                      22       3  86.36%   51-53
R/check_ard_structure.R           27       1  96.30%   26
R/default_stat_labels.R           18       0  100.00%
R/eval_capture_conditions.R       18       0  100.00%
R/get_ard_statistics.R            16       1  93.75%   75
R/nest_for_ard.R                  70       1  98.57%   56
R/print.R                         72       0  100.00%
R/print_ard_conditions.R          75      66  12.00%   60-176
R/process_selectors.R            126       0  100.00%
R/replace_null_statistic.R        11       0  100.00%
R/round5.R                         1       0  100.00%
R/selectors.R                     14       0  100.00%
R/shuffle_ard.R                  134       1  99.25%   268
R/summary_functions.R             58       1  98.28%   91
R/tidy_ard_order.R                25       0  100.00%
R/tidy_as_ard.R                   39      11  71.79%   88-98
R/utils.R                         24       0  100.00%
TOTAL                           1694     124  92.68%

Diff against main

Filename                 Stmts    Miss  Cover
---------------------  -------  ------  --------
R/ard_categorical.R         +1       0  +0.01%
R/ard_complex.R             +1       0  +100.00%
R/ard_continuous.R          +1       0  +0.01%
R/ard_hierarchical.R        +2       0  +100.00%
R/ard_missing.R             +4       0  +100.00%
R/process_selectors.R       +3       0  +100.00%
TOTAL                      +12       0  +0.05%

Results for commit: e36f818

Minimum allowed coverage is 80%

♻️ This comment has been updated with latest results

[github-actions]

Unit Tests Summary

  1 files   85 suites   13s ⏱️
 83 tests  52 ✅ 31 💤 0 ❌
172 runs  127 ✅ 45 💤 0 ❌

Results for commit e36f818.

♻️ This comment has been updated with latest results.

[rparmm]

Missing some minor checks and maybe needs more explicit documentation, otherwise LGTM!

[ddsjoberg]

Thank you for the review @rparmm !!!