adding additional limitation for storage regions (#1682)

Author: jsulz

docs/hub/storage-backends.md

@@ -85,9 +85,10 @@ Xet integrates seamlessly with the Hub's current Python-based workflows. However
 
 While Xet brings fine-grained deduplication and enhanced performance to Git-based storage, some features and platform compatibilities are still in development. As a result, keep the following constraints in mind when working with a Xet-enabled repository:
 
-- **64-bit systems only**: The hf_xet client currently requires a 64-bit architecture; 32-bit systems are not supported.
+- **64-bit systems only**: The `hf_xet` client currently requires a 64-bit architecture; 32-bit systems are not supported.
 - **Partial JavaScript library support**: The [huggingface.js](https://huggingface.co/docs/huggingface.js/index) library has limited functionality with Xet-backed repositories; additional coverage is planned in future releases.
 - **Full web support currently unavailable**: Full support for chunked uploads via the Hub web interface remains under development.
+- **No EU region support**: Support for EU [storage regions](https://huggingface.co/docs/hub/storage-regions) with Xet-backed repositories is planned but remains under development. 
 - **Git client integration (git-xet)**: Planned but remains under development.
 
 ### Deduplication