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

Co-authored-by: Hadrien Croubois <ed1fdb870694988da43d062485927c79190b889d@gmail.com>
(cherry picked from commit aa4b9017882a9ef221648d0768dcf2a8436d869c)

OpenZeppelin/openzeppelin-contracts,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/openzeppelin-contracts