Update functionCall docs
Update functionCall docs

(cherry picked from commit 242400e9ea73b2ca173bee27aa6b9f24b7d1305e)

OpenZeppelin/zep-solidity,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/zeppelin-solidity,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/zeppelin-solidity,OpenZeppelin/zep-solidity