coder_parameter doc has examples with country icons that don't exist

[mattlqx]

https://registry.terraform.io/providers/coder/coder/latest/docs/data-sources/parameter cites:

data "coder_parameter" "example" {
  name        = "Region"
  description = "Specify a region to place your workspace."
  mutable     = false
  type        = "string"
  default     = "asia-central1-a"
  option {
    value = "us-central1-a"
    name  = "US Central"
    icon  = "/icon/usa.svg"
  }
  option {
    value = "asia-central1-a"
    name  = "Asia"
    icon  = "/icon/asia.svg"
  }
}

These country icons do not currently exist in 2.18.4. In fact, when you go to a URL like https://coder.example.com/icon/usa.svg, you'll get a 200 with no body that does some XHR that returns this back to the view:

[matifali]

We will fix. Thanks @mattlqx