adding example specifying conf level in ard_survival_survfit()

[ddsjoberg]

What changes are proposed in this pull request?

• Style this entry in a way that can be copied directly into NEWS.md. (#, @)

Provide more detail here as needed.

Reference GitHub issue associated with pull request. e.g., 'closes #'
closes #216

---

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.
• If a new ard_*() function was added, it passes the ARD structural checks from cards::check_ard_structure().
• If a new ard_*() function was added, set_cli_abort_call() has been set.
• If a new ard_*() function was added and it depends on another package (such as, broom), is_pkg_installed("broom", reference_pkg = "cardx") has been set in the function call and the following added to the roxygen comments: @examplesIf do.call(asNamespace("cardx")$is_pkg_installed, list(pkg = "broom"", reference_pkg = "cardx"))
• Code coverage is suitable for any new functions/features (generally, 100% coverage for new code): devtools::test_coverage()

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

• If a bug was fixed, a unit test was added.
• 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 "# cardx (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]

Unit Tests Summary

  1 files  141 suites   1m 5s ⏱️
140 tests 140 ✅ 0 💤 0 ❌
620 runs  620 ✅ 0 💤 0 ❌

Results for commit 152b98a.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Performance Difference

Test Suite	$Status$	Time on main	$±Time$	$±Tests$	$±Skipped$	$±Failures$	$±Errors$
ard_attributes.survey.design	💔	$0.02$	$+1.61$	$0$	$-1$	$0$	$0$

Additional test case details

Test Suite	$Status$	Time on main	$±Time$	Test Case
ard_aod_wald_test	💚	$1.56$	$-1.27$	ard_aod_wald_test_works
ard_attributes.survey.design	💔	$0.02$	$+1.61$	ard_attributes.survey.design_works
ard_categorical.survey.design	💔	$15.61$	$+1.38$	ard_categorical.survey.design_works
ard_continuous.survey.design	💚	$21.67$	$-7.04$	unstratified_ard_continuous.survey.design_works
construction_helpers	💔	$0.40$	$+1.80$	construct_model_works
proportion_ci	💔	$0.13$	$+1.57$	check_the_proportion_ci__functions_work

Results for commit a6aa147

♻️ This comment has been updated with latest results.

[github-actions]

Code Coverage Summary

Filename                                Stmts    Miss  Cover    Missing
------------------------------------  -------  ------  -------  --------------------------
R/add_total_n.survey.design.R              12       0  100.00%
R/ard_aod_wald_test.R                      77       8  89.61%   38-43, 93, 96
R/ard_attributes.survey.design.R            2       0  100.00%
R/ard_car_anova.R                          45       2  95.56%   62, 65
R/ard_car_vif.R                            62       1  98.39%   87
R/ard_categorical_ci.R                     96       1  98.96%   83
R/ard_categorical_ci.survey.design.R      128       3  97.66%   152-153, 179
R/ard_categorical.survey.design.R         391       8  97.95%   77, 226-229, 273, 515, 529
R/ard_continuous_ci.R                      28       1  96.43%   38
R/ard_continuous_ci.survey.design.R       137       0  100.00%
R/ard_continuous.survey.design.R          201       3  98.51%   86, 177, 187
R/ard_dichotomous.survey.design.R          73       3  95.89%   51, 156, 161
R/ard_effectsize_cohens_d.R               103       2  98.06%   69, 122
R/ard_effectsize_hedges_g.R                91       2  97.80%   68, 120
R/ard_emmeans_mean_difference.R            70       0  100.00%
R/ard_missing.survey.design.R              79       1  98.73%   52
R/ard_regression_basic.R                   16       1  93.75%   46
R/ard_regression.R                         73       0  100.00%
R/ard_smd_smd.R                            69       5  92.75%   57, 83-86
R/ard_stats_anova.R                        95       0  100.00%
R/ard_stats_aov.R                          46       0  100.00%
R/ard_stats_chisq_test.R                   40       1  97.50%   39
R/ard_stats_fisher_test.R                  43       1  97.67%   42
R/ard_stats_kruskal_test.R                 36       1  97.22%   38
R/ard_stats_mcnemar_test.R                 80       2  97.50%   63, 106
R/ard_stats_mood_test.R                    49       1  97.96%   45
R/ard_stats_oneway_test.R                  39       0  100.00%
R/ard_stats_poisson_test.R                 76       1  98.68%   59
R/ard_stats_prop_test.R                    85       1  98.82%   43
R/ard_stats_t_test_onesample.R             41       0  100.00%
R/ard_stats_t_test.R                      112       2  98.21%   65, 111
R/ard_stats_wilcox_test_onesample.R        42       0  100.00%
R/ard_stats_wilcox_test.R                  99       2  97.98%   65, 117
R/ard_survey_svychisq.R                    38       1  97.37%   44
R/ard_survey_svyranktest.R                 54       1  98.15%   44
R/ard_survey_svyttest.R                    53       1  98.11%   42
R/ard_survival_survdiff.R                  89       0  100.00%
R/ard_survival_survfit_diff.R              76       0  100.00%
R/ard_survival_survfit.R                  174      11  93.68%   79-81, 95-97, 128-132
R/construction_helpers.R                  106      10  90.57%   160-175, 189, 248
R/proportion_ci.R                         195       1  99.49%   454
TOTAL                                    3421      78  97.72%

Diff against main

Filename      Stmts    Miss  Cover
----------  -------  ------  --------
TOTAL             0       0  +100.00%

Results for commit: 152b98a

Minimum allowed coverage is 80%

♻️ This comment has been updated with latest results