Interesting issue. One that I came across before. The npm-ini package has a similar issue related to generating INI files (npm/ini@6a3cb38).

Their solution was to use define line endings based upon detecting of the OS, but allow the override if required.

Is that a "better" option? If you are on a Windows environment, it is pretty much a standard thing that the files will be made with CRLF, and so, having to set an option for the expected default behaviour would seem a bit odd.

As the binaries are built for different operating systems, is it acceptable to have the default value for line endings based upon the target OS?

I'm not a go expert, and so whilst this idea may be fine for npm-ini, it may not be "how things are done" in Go apps.

That would require that everyone executing terraform-docs does so from the same OS as well as having the same vcs client configurations, right? Any contributor for my terraform project who used windows when we're on *nix or vice-versa would generate docs that flip the line endings. Plus, you can only run terraform docs --output-check as part of your CI process with one OS, so flipping between them isn't nice either. And that's not really backward compatible, since however many windows clients would suddenly start using CRLF line endings with little explanation.