chore: update changelog

Author: tconbeer

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+### Formatting Changes and Bug Fixes
+
+- sqlfmt now lexes and formats BigQuery hexadecimal literals as numbers, and no longer adds a space between `0` and `x` ([#696](https://github.com/tconbeer/sqlfmt/issues/696) - thank you [@KMontag42](https://github.com/KMontag42) and [@snrsw](https://github.com/snrsw)!).
+
 ## [0.27.0] - 2025-07-28
 
 ### Features