fix: refine performance details for Horizon Beta stealth model in release notes

Author: hannesrudolph

docs/update-notes/v3.25.6.mdx

@@ -17,9 +17,8 @@ This release features support for the new Horizon Beta stealth model, cloud prov
 
 We've optimized support for OpenRouter's new stealth model Horizon Beta ([#6577](https://github.com/RooCodeInc/Roo-Code/pull/6577)):
 
-- **Improved Performance**: Set max tokens to 32k for better response times (reduced from 128k default)
+- **Improved Performance**: Set max tokens to 32k (reduced from 128k default)
 - **Free to Use**: Thanks to OpenRouter, Horizon Beta is an improved version of Horizon Alpha and remains free
-- **Stealth Model**: Designed for enhanced privacy and performance
 
 A big thanks to OpenRouter for providing this innovative stealth model to the community!