fix: add recommended hook execution order

standard/ERCs/erc-6900.md

@@ -528,6 +528,10 @@ During execution uninstallation, the account MUST correctly clear flags and othe
 - the account SHOULD call `onUnInstall` on the execution module to initialize the states and track call success if required by user.
 - the account MUST emit `ExecutionUninstalled` as defined in the interface for all uninstalled executions.
 
+#### Hook execution order
+
+It is RECOMMENDED that an account implementer runs hooks in first installed first executed order. However, an account MAY implement a different execution order.
+
 ### Validation Call Flow
 
 Modular accounts support three different calls flows for validation: user op validation, runtime validation, and signature validation. User op validation happens within the account's implementation of the function `validateUserOp`, defined in the ERC-4337 interface `IAccount`. Runtime validation happens through the dispatcher function `executeWithAuthorization`, or when using direct call validation. Signature validation happens within the account's implementation of the function `isValidSignature`, defined in ERC-1271.