List all geographic layers available.
Examples
# \donttest{
ha_set("chicagohealthatlas.org")
ha_layers()
#> # A tibble: 7 × 3
#> layer_name layer_key layer_url
#> <chr> <chr> <chr>
#> 1 Community areas neighborhood https://media.metop.io/shapes/ancestries/communi…
#> 2 ZIP Codes zip https://media.metop.io/shapes/teams/chicago-heal…
#> 3 Census Tracts tract-2020 https://media.metop.io/shapes/teams/chicago-heal…
#> 4 Chicago place https://media.metop.io/shapes/teams/chicago-heal…
#> 5 United States us https://media.metop.io/shapes/us.topo.json
#> 6 States state https://media.metop.io/shapes/teams/chicago-heal…
#> 7 Counties county https://media.metop.io/shapes/teams/chicago-heal…
# }