fix: adding fungible trait example (#226)

Author: nhussein11

polkadot-protocol/basics/accounts.md

@@ -123,7 +123,19 @@ This modular and flexible system of reference counters tightly controls the life
 In the Polkadot ecosystem, account balances are categorized into different types based on how the funds are utilized and their availability. These balance types determine the actions that can be performed, such as transferring tokens, paying transaction fees, or participating in governance activities. Understanding these balance types helps developers manage user accounts and implement balance-dependent logic.
 
 !!! tip "A more efficient distribution of account balance types is in development"
-    Soon, pallets in the Polkadot SDK will implement the [`fungible` trait](https://paritytech.github.io/polkadot-sdk/master/frame_support/traits/tokens/fungible/index.html){target=\_blank} (see the [tracking issue](https://github.com/paritytech/polkadot-sdk/issues/226){target=\_blank} for more details). This update will enable more efficient use of account balances, allowing the free balance to be utilized for on-chain activities such as setting proxies and managing identities.
+    Soon, pallets in the Polkadot SDK will implement the [`Fungible` trait](https://paritytech.github.io/polkadot-sdk/master/frame_support/traits/tokens/fungible/index.html){target=\_blank} (see the [tracking issue](https://github.com/paritytech/polkadot-sdk/issues/226){target=\_blank} for more details). For example, the [`transaction-storage`](https://paritytech.github.io/polkadot-sdk/master/pallet_transaction_storage/index.html){target=\_blank} pallet changed the implementation of the [`Currency`](https://paritytech.github.io/polkadot-sdk/master/frame_support/traits/tokens/currency/index.html){target=\_blank} trait (see the [Refactor transaction storage pallet to use fungible traits](https://github.com/paritytech/polkadot-sdk/pull/1800){target=\_blank} PR for further details):
+
+    ```rust
+    type BalanceOf<T> = <<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
+    ```
+    
+    To the [`Fungible`](https://paritytech.github.io/polkadot-sdk/master/frame_support/traits/tokens/fungible/index.html){target=\_blank} trait:
+
+    ```rust
+    type BalanceOf<T> = <<T as Config>::Currency as FnInspect<<T as frame_system::Config>::AccountId>>::Balance;
+    ```
+    
+    This update will enable more efficient use of account balances, allowing the free balance to be utilized for on-chain activities such as setting proxies and managing identities.
 
 ### Balance Types