feat: Add inform_latest_results()

[gadenbuie]

A small helper to list the currently failing tests from the latest nightly run.

pkgload::load_all()

inform_latest_results()
#> <https://rstudio.github.io/shinycoreci/results/2023/12/07/>
#> ✖ 6 tests failed:
#> - `145-dt-replacedata`
#> - `178-delayed-widget`
#> - `180-delayed-staticwidget`
#> - `301-bs-themes`
#> - `308-sidebar-kitchen-sink`
#> - `313-bslib-card-tab-focus`

I find it helpful to start looking into test failures with a list like this, otherwise it's easy to resolve all of the snaphots with fix_snaps() and miss other types of test failures that didn't involve snapshots.

[schloerke]

Missing docs and export tag

[gadenbuie]

lol I thought it could be an internal helper function.