Update audio.md

Author: eric-urban

articles/ai-services/openai/concepts/audio.md

@@ -20,7 +20,7 @@ Audio models in Azure OpenAI are available via the `realtime`, `completions`, an
 
 For information about the available audio models per region in Azure OpenAI Service, see the [audio models](models.md?tabs=standard-audio#standard-deployment-regional-models-by-endpoint), [standard models by endpoint](models.md?tabs=standard-audio#standard-deployment-regional-models-by-endpoint), and [global standard model availability](models.md?tabs=standard-audio#global-standard-model-availability) documentation.
 
-### GPT-4o audio Realtime API
+## GPT-4o audio Realtime API
 
 GPT-4o real-time audio is designed to handle real-time, low-latency conversational interactions, making it a great fit for support agents, assistants, translators, and other use cases that need highly responsive back-and-forth with a user. For more information on how to use GPT-4o real-time audio, see the [GPT-4o real-time audio quickstart](../realtime-audio-quickstart.md) and [how to use GPT-4o audio](../how-to/realtime-audio.md).