List all geographic layers available.
Examples
# \donttest{
ha_set("chicagohealthatlas.org")
ha_layers()
#> # A tibble: 4 × 4
#> layer_name layer_key layer_description layer_url
#> <chr> <chr> <chr> <chr>
#> 1 Community areas neighborhood The city of Chicago is divided into 77… https://…
#> 2 ZIP Codes zip The ZIP code is a basic unit of geogra… https://…
#> 3 Census Tracts tract-2020 Census tracts are small geographies de… https://…
#> 4 Chicago place Cities, towns, villages, and boroughs,… https://…
# }