Improve `ERC20FlashMint` documentation (#3719)
Improve `ERC20FlashMint` documentation (#3719)

Co-authored-by: Hadrien Croubois <ed1fdb870694988da43d062485927c79190b889d@gmail.com>
OpenZeppelin/openzeppelin-contracts,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/openzeppelin-contracts