Improve SampleToInsertRatio rate limiter documentation.
Improve SampleToInsertRatio rate limiter documentation.

PiperOrigin-RevId: 351359846
Change-Id: Iadb3d9fbb6d5d89b0c121d6ddff28ef74cbcd943

deepmind/reverb,deepmind/reverb,deepmind/reverb,deepmind/reverb