`src/doc/build-man.sh` is not able to run on platforms missing `sh`

[weihanglo]

Problem

From #11646 (comment), people struggle to run src/doc/build-man.sh on Windows. This might prevent Windows users from contributing Cargo documentations. We may want to find a way making every contributor feel inclusive without introducing more external tool dependencies.

Proposed Solution

Two options off the top of my head:

• EASY: Translate src/doc/build-man.sh to Windows batch script or powershell.
• EASY: Use a python script instead. See this comment.
• HARD?: Introduce some workflow like cargo-xtask (blocked on nested workspaces feature).

Need to take care of crates/mdman/build-man.sh as well.

Notes

Was reading this article and it reminded me this issue.

[Muscraft]

One solution could be converting to a python script. The biggest problem with making it a python script is that python is not installed by default for all OS. I think it could be reasonable to say python is required as we already have publish.py, and most contributors should have python already installed.

[epage]

Another option is cargo-script.

Overall, I assume a cargo-xtask makes the most sense if we can figure out the workspace issue.