Update SafeERC20.sol (#2246)
Update SafeERC20.sol (#2246)

tweak intro dev comment to reflect more typical use case, wrapping an `IERC20` reference for a deposit contract using others' ERC-20 tokens. I might be mistaken ~ but typically SafeERC20 won't be used in conjunction with ERC20 for OZ token deployments?
OpenZeppelin/openzeppelin-contracts,OpenZeppelin/zep-solidity,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/zep-solidity,OpenZeppelin/zeppelin-solidity,OpenZeppelin/zeppelin-solidity