testdata: Amend full-example/main.tf, add local value with provider function to verify terraform-docs can properly parse

Signed-off-by: Brittan DeYoung <32572259+brittandeyoung@users.noreply.github.com>

terraform/testdata/full-example/main.tf

@@ -29,5 +29,9 @@ module "foo" {
 }
 
 module "foobar" {
-  source  = "git@github.com:module/path?ref=v7.8.9"
+  source = "git@github.com:module/path?ref=v7.8.9"
+}
+
+locals {
+  arn = provider::aws::arn_parse("arn:aws:iam::444455556666:role/example")
 }