feat: notify developers about GMP token events they can emit (#1262)

src/content/docs/dev/general-message-passing/gmp-messages.mdx

@@ -76,3 +76,52 @@ function _execute(
 ```
 
 **Learn More:** For a detailed tutorial on building a full-stack interchain decentralized application with Next.js, Solidity, and Axelar's General Message Passing `callContract` to send messages between blockchains, check out our comprehensive guide: [Build a Full-Stack Interchain Application With Next.js, Solidity & Axelar](https://www.axelar.network/blog/how-to-build-interchain-dapp-with-next-js-solidity-and-axelar).
+
+If you are implementing any underlying token transfer capabilities, you should import the [`InterchainTransferSent`](https://github.com/axelarnetwork/axelar-gmp-sdk-solidity/blob/main/contracts/interfaces/IInterchainTransfer.sol) or [`InterchainTransferReceived`](https://github.com/axelarnetwork/axelar-gmp-sdk-solidity/blob/main/contracts/interfaces/IInterchainTransfer.sol) interfaces and emit events as appropriate so that these events can be tracked.
+```
+interface IInterchainTransferSent {
+    /**
+     * @dev Emitted when a GMP transfer is sent, providing details for volume tracking.
+     * @param destinationChain The Axelar chain identifier of the destination chain.
+     * @param destinationContractAddress The address of the contract on the destination chain that receives the transfer.
+     * @param recipient The address of the final recipient of the transferred assets on the destination chain.
+     * @param token The address of the token contract on the source chain.
+     * @param amount The amount (in atomic units) of tokens transferred.
+     */
+    event InterchainTransferSent(
+        string destinationChain,
+        string destinationContractAddress,
+        address indexed sender,
+        bytes recipient,
+        address indexed token,
+        uint256 amount
+    );
+}
+
+/**
+ * @title IInterchainTransferReceived
+ * @dev Interface for tracking asset value transfers using General Message Passing (GMP) calls in the Axelar Network.
+ * This interface defines an event that should be emitted when a GMP transfer is received,
+ * allowing for standardized volume tracking across different implementations.
+ */
+interface IInterchainTransferReceived {
+    /**
+     * @dev Emitted when an interchain transfer is received, providing details for volume tracking.
+     * @param sourceChain The Axelar chain identifier of the source chain.
+     * @param sourceAddress The address of the contract that initiated the transfer on the source chain.
+     * @param sender The address of the sender in case it is different from the source contract address
+     * @param recipient The address of the final recipient of the transferred assets on the destination chain.
+     * @param token The address of the token contract on the destination chain.
+     * @param amount The amount (in atomic units) of tokens received.
+     */
+    event InterchainTransferReceived(
+        string sourceChain,
+        string sourceAddress,
+        bytes sender,
+        address indexed recipient,
+        address indexed token,
+        uint256 amount
+    );
+}
+```
+