overflow classification and error is inconsistent on divide by zero in mulDiv#201

### What version of PRBMath are you using? 5959ef59f906d689c2472ed08797872a1cc00644 ### What version of Solidity are you using? 0.8.19 ### Describe the bug the unchecked division at the start of mulDiv actually jumps into a divide by zero check even though it is "unchecked". this is probably a good thing because `mulDiv(0, 1e18, 0)` and `mulDiv(1, 1e18, 0)` and other examples cause `prod1` to be `0` which is treated as a "non overflow case" according to the comments, but we still don't want to allow dividing by zero here. further down in the same fn, divide by 0 triggers an "overflow" error if `prod1 >= denominator` and the denominator is `0`. i don't think this is dangerous but it leads to inconsistent errors which makes fuzzing downstream quite fiddly if we want to assert on the error selector with foundry. the same error should be thrown for "divide by 0" regardless of the internal `prod0` and `prod1` logic.