Update kubectl_path_documents example doc. (#140)

Example uses kubectl_file_documents instead of kubectl_path_documents.
for_each has to be a set or a map and thus toset() is needed.
This update closes #135.

docs/data-sources/kubectl_path_documents.md

@@ -19,7 +19,7 @@ data "kubectl_path_documents" "docs" {
 }
 
 resource "kubectl_manifest" "test" {
-    for_each  = data.kubectl_file_documents.docs.manifests
+    for_each  = toset(data.kubectl_path_documents.docs.documents)
     yaml_body = each.value
 }
 ```