Update the rewardedads documentation to reflect it's release state.
Update the rewardedads documentation to reflect it's release state.

PiperOrigin-RevId: 245332714
GitOrigin-RevId: 56556412700aeac006a61105cda55059f486e8c7

google/tink,google/tink,google/tink,google/tink,google/tink,google/tink,google/tink,google/tink