doc(indexeddb): add changelog entry for separating media content and metadata in IndexedDB

Signed-off-by: Michael Goldenberg <[email protected]>

Author: mgoldenberg

crates/matrix-sdk-indexeddb/CHANGELOG.md

@@ -6,6 +6,9 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased] - ReleaseDate
 
+- Improve performance of certain media queries in `MediaStore` implementation by storing media content and media metadata
+  in separate object stores in IndexedDB (see [#5795](https://github.com/matrix-org/matrix-rust-sdk/pull/5795)).
+
 ## [0.14.0] - 2025-09-04
 
 No notable changes in this release.
@@ -43,6 +46,7 @@ No notable changes in this release.
 
 - `save_change` performance improvement, all encryption and serialization
   is done now outside of the db transaction.
+
 ### Bug Fixes
 
 - Use the `DisplayName` struct to protect against homoglyph attacks.