All the help files are open source now! PowerShell Team · GitHub is the starting point. You can either file an issue, or just fork the repo, fix the problem, and submit a pull request
There are separate sub folders for documentation. And no, you definitely don’t create a new repository :). It might be easier to find what you’re after and just file an issue against it, or use the teams UserVoice page. But it’s worth your time to read up on GitHub and how to use Git. It’s a big part of powershell now.