chore: added link to the state migration for zero balance prunning bu…

…g fix (cosmos#9702)

## Description

Not sure if we should add it as a new entry. Tentatively, I've added migration to the same item as the bug fix.

CHANGELOG.md

@@ -222,7 +222,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (x/bank) [\#8434](https://github.com/cosmos/cosmos-sdk/pull/8434) Fix legacy REST API `GET /bank/total` and `GET /bank/total/{denom}` in swagger
 * (x/slashing) [\#8427](https://github.com/cosmos/cosmos-sdk/pull/8427) Fix query signing infos command
 * (x/bank/types) [\#9112](https://github.com/cosmos/cosmos-sdk/pull/9112) fix AddressFromBalancesStore address length overflow
-* (x/bank) [\#9229](https://github.com/cosmos/cosmos-sdk/pull/9229) Now zero coin balances cannot be added to balances & supply stores. If any denom becomes zero corresponding key gets deleted from store.
+* (x/bank) [\#9229](https://github.com/cosmos/cosmos-sdk/pull/9229) Now zero coin balances cannot be added to balances & supply stores. If any denom becomes zero corresponding key gets deleted from store. State migration: [\#9664](https://github.com/cosmos/cosmos-sdk/pull/9664).
 * [\#9363](https://github.com/cosmos/cosmos-sdk/pull/9363) Check store key uniqueness in app wiring.
 * [\#9460](https://github.com/cosmos/cosmos-sdk/pull/9460) Fix lint error in `MigratePrefixAddress`.
 * [\#9480](https://github.com/cosmos/cosmos-sdk/pull/9480) Fix added keys when using `--dry-run`.