docs: add information about token permissions with tfe_registry_module (#953)

* docs: add information about token permissions with tfe_registry_module

With this, it is clear from the documentation that only very specific tokens
have the permission to manage registry modules.

* fixup! docs: add information about token permissions with tfe_registry_module

* Discard changes to CHANGELOG.md

* fixup: typo

Author: morremeyer

website/docs/r/registry_module.html.markdown

@@ -11,6 +11,8 @@ HCP Terraform's private module registry helps you share Terraform modules across
 
 ~> **NOTE:** The `agent_execution_mode` and `agent_pool_id` fields in the `test_config` block are currently in beta and are not available to all users. These features are subject to change or be removed.
 
+**Note**: To manage this resource, the token used with the provider needs to be for a team with **owner** permissions or a user who has the permissions explicitly assigned. Crucially, this **does not work** with an organization token! See the [API Access Levels](https://developer.hashicorp.com/terraform/cloud-docs/users-teams-organizations/api-tokens#access-levels) documentation for more information.
+
 ## Example Usage
 
 Basic usage with VCS: