s3 output docs are badly out of date

### Describe the bug

The documentation on https://docs.fluentd.org/output/s3 is very out of date.  

### Link to the problematic documentation

https://docs.fluentd.org/output/s3

### Expected explanation

https://github.com/fluent/fluent-plugin-s3/tree/master/docs

Sync the documentation from the s3 repo, or just link to it.

### Additional context

_No response_