doc: add release note for -getinfo displaying multiwallet balances

Author: jonatack

doc/release-notes-18594.md

@@ -0,0 +1,5 @@
+## CLI
+
+The `bitcoin-cli -getinfo` command now displays the wallet name and balance for
+each of the loaded wallets when more than one is loaded (e.g. in multiwallet
+mode) and a wallet is not specified with `-rpcwallet`. (#18594)