WIP: Output JS-compatible line numbers

[helixbass]

@GeoffreyBooth re-opening against master

See original PR: #5264

[thisredone]

Hey, are you still working on this? coffeescript really needs line numbers in stack traces fixed

[helixbass]

This should only affect line numbers in files which use irregular linebreak characters, so not sure if it's likely to address your issue

Can you give an example though where it's currently incorrect?

[thisredone]

There's something here: #5129
It's sort of strange. I guess maybe no one but me is using the coffee binary but I honestly don't remember the last time I've worked on a project (and I work on a lot of projects of all sizes on both Linux and Windows) that had correct stack traces.

[GeoffreyBooth]

I don't doubt there's an issue, but to fix it we need a minimal reproducible case. If you could provide as small an example as possible where the line numbers are wrong, either for stack traces or source maps, that would give us what we need to fix the bug.

[wdavidw]

Just to confirm on my side, line numbers are incorrect with .coffee.md extensions, it has been the case for ages.