Added xAI to HIPAA list (#1104)

Added xAI to all three model lists on the HIPAA page.

Author: stephenvapiai

fern/security-and-privacy/hipaa.mdx

@@ -67,6 +67,7 @@ When enabling HIPAA compliance, only HIPAA compliant providers may be chosen.
 - **Custom LLM**
 - **Baseten**
 - **Together AI**
+- **xAI**
 
 ### Voice Providers (TTS)
 
@@ -76,12 +77,14 @@ When enabling HIPAA compliance, only HIPAA compliant providers may be chosen.
 - **Rime AI**
 - **Deepgram**
 - **Azure**
+- **xAI**
 
 ### Transcription Providers (STT)
 
 - **Azure**
 - **Deepgram**
 - **Soniox**
+- **xAI**
 
 # FAQs