Firestore/CHANGELOG.md: Copied message from firebase/firebase-android-sdk#3664

Author: dconeybe

Firestore/CHANGELOG.md

@@ -1,6 +1,6 @@
 # Unreleased
-- [feature] Added the ability to specify the maximum number of attempts to
-  execute a transaction (#9838)
+- [feature] Added `TransactionOptions` to control how many times a transaction
+  will retry commits before failing (#9838).
 
 # 9.0.0
 - [fixed] Fixed CMake build errors when building with Xcode 13.3.1 (#9702).