docs: note to checkout out openai docs first

docs/usage/speech-to-text.md

@@ -1,11 +1,12 @@
-https://platform.openai.com/docs/api-reference/audio/createTranscription
-https://platform.openai.com/docs/guides/speech-to-text
-
 TODO: add a note about automatic downloads
 TODO: mention streaming
 TODO: add a demo
 TODO: talk about audio format
 
+!!! note
+
+    Before proceeding, make sure you are familiar with the [OpenAI Speech-to-Text](https://platform.openai.com/docs/guides/speech-to-text) and the relevant [OpenAI API reference](https://platform.openai.com/docs/api-reference/audio/createTranscription)
+
 ## Curl
 
 ```bash

docs/usage/text-to-speech.md

@@ -2,12 +2,14 @@
 
     This feature not supported on ARM devices only x86_64. I was unable to build [piper-phonemize](https://github.com/rhasspy/piper-phonemize)(my [fork](https://github.com/fedirz/piper-phonemize))
 
-https://platform.openai.com/docs/api-reference/audio/createSpeech
-https://platform.openai.com/docs/guides/text-to-speech
 http://localhost:8001/faster-whisper-server/api/
 TODO: add a note about automatic downloads
 TODO: add a demo
 
+!!! note
+
+    Before proceeding, make sure you are familiar with the [OpenAI Text-to-Speech](https://platform.openai.com/docs/guides/text-to-speech) and the relevant [OpenAI API reference](https://platform.openai.com/docs/api-reference/audio/createSpeech)
+
 ## Prerequisite
 
 Download the piper voices from [HuggingFace model repository](https://huggingface.co/rhasspy/piper-voices)