Apply suggestions from code review

Author: ncooke3

FirebaseAuth/CHANGELOG.md

@@ -6,10 +6,10 @@
   current user is unexpectedly `nil` at startup.
 - [fixed] Restore Firebase 10 decoding behavior to prevent user provider data
   from always being decoded as `nil` . Note that this fix was only needed for
-  cases Firebase 11 was reading data written by Firebase 10. (#14011)
+  cases where Firebase 11 was reading data written by Firebase 10. (#14011)
 - [fixed] Restore Firebase 10 decoding behavior to prevent user provider data
   from being decoded as `nil` when a user has multiple linked providers. Note
-  that this fix was only needed for cases Firebase 11 was reading data written
+  that this fix was only needed for cases where Firebase 11 was reading data written
   by Firebase 10. Note that this fix will not be in the 11.6.0 zip and
   Carthage distributions, but will be included from 11.6.0 onwards. (#14011)