Agora RTC Objective-C API Reference Refactor

### - h -

- H265_TRANSCODE_RESULT_CONFLICTED : agora::rtc
- H265_TRANSCODE_RESULT_FORBIDDEN : agora::rtc
- H265_TRANSCODE_RESULT_NOT_FOUND : agora::rtc
- H265_TRANSCODE_RESULT_NOT_SUPPORTED : agora::rtc
- H265_TRANSCODE_RESULT_REQUEST_INVALID : agora::rtc
- H265_TRANSCODE_RESULT_SERVER_INTERNAL_ERROR : agora::rtc
- H265_TRANSCODE_RESULT_SERVICE_UNAVAILABLE : agora::rtc
- H265_TRANSCODE_RESULT_SUCCESS : agora::rtc
- H265_TRANSCODE_RESULT_TOKEN_EXPIRED : agora::rtc
- H265_TRANSCODE_RESULT_TOO_OFTEN : agora::rtc
- H265_TRANSCODE_RESULT_UNAUTHORIZED : agora::rtc
- H265_TRANSCODE_RESULT_UNKNOWN : agora::rtc
- HEADPHONE_EQUALIZER_INEAR : agora::rtc
- HEADPHONE_EQUALIZER_OFF : agora::rtc
- HEADPHONE_EQUALIZER_OVEREAR : agora::rtc
- HIGH : agora::rtc
- HIGHEST : agora::rtc
- HTTP_PROXY_TYPE : agora::rtc
- HTTPS_PROXY_TYPE : agora::rtc