feat: eip712 type hash

[0xrusowsky]

Adds a new cheatcode to safely generate hashes following the EIP-712 spec.

implementation details

As highlighted on:

• Cheatcode: EIP712 canonical hashing #4818

due to the lack of polymorphism, it is not possible for the cheatcode to accept a struct. Because of that, users must provide a string.

This initial impl requires users to input the full string representation of the type (later on we can iterate and attempt to figure the type from the artifact).

Users are not required to pass sorted types, and can also add spaces after commas. See the test cases for a better understanding:

// CANONICAL TYPE
bytes32 constant _PERMIT_SINGLE_TYPEHASH = keccak256(
    "PermitSingle(PermitDetails details,address spender,uint256 sigDeadline)PermitDetails(address token,uint160 amount,uint48 expiration,uint48 nonce)"
);

function test_canHashCanonicalTypes() public {
    typeHash = vm.eip712HashType(
        "PermitSingle(PermitDetails details,address spender,uint256 sigDeadline)PermitDetails(address token,uint160 amount,uint48 expiration,uint48 nonce)"
    );
    assertEq(typeHash, _PERMIT_SINGLE_TYPEHASH);
}

function test_canHashMessyTypes() public {
    typeHash = vm.eip712HashType(
        "PermitDetails(address token, uint160 amount, uint48 expiration, uint48 nonce) PermitSingle(PermitDetails details, address spender, uint256 sigDeadline)"
    );
    assertEq(typeHash, _PERMIT_SINGLE_TYPEHASH);
}