fix: support mmdc on windows

[bbawj]

I am not sure if Windows platform support is of any importance but I encountered an issue where mmdc cannot be found on Windows. This is due to this issue where Command::new() on Windows works in this way: "if the file has a different extension, a filename including the extension needs to be provided, otherwise the file won’t be found.".

Since mmdc on Windows is an alias for the mmdc.cmd script and not an exe, this updates the name used to find the mmdc tool.

[mfontanini]

I am not sure if Windows platform support is of any importance

It is, I just didn't test this properly over there. I assumed since things like invoking cargo or other tools work this would work too but I guess not. Thanks!

[mfontanini]

Looks like you need to run cargo fmt for the CI to pass.

[mfontanini]

Thanks again!