include replay log paragraph in replay documentation

Include the following in replay documentation, which currently is only included in the replay file.

This log may contain specific values for IDs or names that were generated during fuzzing, using the fuzzing dictionary. Such names will be re-played without modification. You must update the replay log manually with any changes required to execute the requests in your environment (for example, replacing pre-created account, subscription, or other resource IDs, as needed).