(Documentation issue) Client Retry link is 404 in multiple files

Some of Java doc includes a link to https://github.com/googleapis/google-cloud-java/blob/main/docs/client_retries.md which is 404. It appears as a link on API document.

<img width="1146" height="743" alt="Image" src="https://github.com/user-attachments/assets/6e28dbaf-fb82-412a-bf0b-38f92e0d5e2d" />

Probably the right place is https://docs.cloud.google.com/java/docs/client-retries now.

