Motivation
We are ignoring raise NotImplementedError lines in coverage, but if the EM rules are being used then the message will need to be specified outside the raise line, conventionally starting with msg = (I say convention because ruff's autofix uses this variable name). We should ignore these lines too.

Arguments against; perhaps this is not as conventional as it seems, and it will have false positives.

Summary of desired enhancement
Consider whether we want this logic or not. Also consider it for development, even if not as a feature of usethis.