Add a list of provider that uses terraform-plugin-docs

### Terraform CLI and terraform-plugin-docs Versions

any

### Use Cases or Problem Statement

As a new user of terraform-plugin-docs I would like to see examples in the wild of provider using terraform-plugin-docs so that I can see their template and their files architecture as a example for implementing my own.

### Proposal

Have a list either in a dedicated file and/or in the readme of known providers that uses this

### How much impact is this issue causing?

Low

### Additional Information

_No response_

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct