This PR updates the image comparison methods to report a failure message rather than just a boolean of whether the comparison passed or failed. This failure message provides more insight into the reason why a snapshot assertion failed. This is especially helpful when the image differences are subtle - such as the "ghost" differences mentioned in https://github.com/pointfreeco/swift-snapshot-testing/pull/628#issuecomment-1250224235
A follow-up to https://github.com/pointfreeco/swift-snapshot-testing/pull/628#issuecomment-1250404163
This PR updates the image comparison methods to report a failure message rather than just a boolean of whether the comparison passed or failed. This failure message provides more insight into the reason why a snapshot assertion failed. This is especially helpful when the image differences are subtle - such as the "ghost" differences mentioned in https://github.com/pointfreeco/swift-snapshot-testing/pull/628#issuecomment-1250224235