Agora RTC Objective-C API Reference Refactor

### - r -

- rangeID : AgoraColorSpace
- rawData : AgoraRtmMessage
- reason : AgoraRtmErrorInfo , AgoraRtmLinkStateEvent , AgoraRtmTokenEvent
- reasonCode : AgoraRtmLinkStateEvent
- receivedBitrate : AgoraRtcRemoteAudioStats , AgoraRtcRemoteVideoStats
- receivedSampleRate : AgoraRtcRemoteAudioStats
- reconnectTimeout : AgoraRtmClientConfig
- recorderFileName : AgoraMediaRecorderInfo
- recorderInfoUpdateInterval : AgoraMediaRecorderConfiguration
- recordingChannel : AgoraAudioRecordingConfiguration
- recordTs : AgoraRtmMetadataOptions
- recordUserId : AgoraRtmMetadataOptions
- rect : AgoraTranscodingVideoStream
- rednessLevel : AgoraBeautyOptions
- releaseTime : AgoraMusic
- remoteJoined2PacketReceived : AgoraVideoRenderingTracingInfo
- remoteJoined2SetView : AgoraVideoRenderingTracingInfo
- remoteJoined2UnmuteVideo : AgoraVideoRenderingTracingInfo
- remoteUid : AgoraExtensionInfo
- remoteUserUid : AgoraMixedAudioStream , AgoraTranscodingVideoStream
- remoteVisible : AgoraMetaAvatarModelInfo
- rendererOutputFrameRate : AgoraRtcRemoteVideoStats
- renderMode : AgoraRtcVideoCanvas
- renderTimeMs : AgoraAudioFrame , AgoraExtVideoFrame , AgoraOutputVideoFrame , AgoraVideoFilterFrame
- resolution : AgoraMvProperty
- revision : AgoraRtmMetadataItem
- right : AgoraMetaPositionInfo , AgoraSpatialAudioZone
- rightLength : AgoraSpatialAudioZone
- roomName : AgoraMetaEnterSceneConfig
- rotation : AgoraEncodedVideoFrameInfo , AgoraExtVideoFrame , AgoraOutputVideoFrame , AgoraRtcMediaStreamInfo , AgoraVideoFilterFrame , AgoraVideoFrame
- rtcEngine : AgoraLocalSpatialAudioConfig , AgoraMetaServiceConfig , AgoraMusicContentCenterConfig
- rtcToken : AgoraMetaServiceConfig
- rtmToken : AgoraMetaServiceConfig
- rtpTimestamp : AgoraAudioFrame
- rtt : AgoraLastmileProbeResult
- rxAudioBytes : AgoraChannelStats , AgoraRtcRemoteAudioStats
- rxAudioKBitrate : AgoraChannelStats
- rxBytes : AgoraChannelStats
- rxKBitrate : AgoraChannelStats
- rxKBitRate : AgoraPathStats
- rxPacketLossRate : AgoraChannelStats
- rxStreamType : AgoraRtcRemoteVideoStats
- rxVideoBytes : AgoraChannelStats , AgoraRtcRemoteVideoStats
- rxVideoKBitrate : AgoraChannelStats