toWadUnsafe
Authors: Solmate (https://github.com/transmissions11/solmate/blob/main/src/utils/SignedWadMath.sol), Modified from Remco Bloemen (https://xn--2-umb.com/22/exp-ln/index.html)
Signed 18 decimal fixed point (wad) arithmetic library.
Will not revert on overflow, only use where overflow is not possible.
function toWadUnsafe(uint256 x) pure returns (int256 r);