Command prompt escaping in `Process.quote_windows` about crystal

[HertzDevil]

Sometimes I've been thinking what the shell would be for a hypothetical MinGW-based toolchain. Crystal programs built with it can definitely expect the availability of sh.exe as a default POSIX shell. So maybe replacing shell: true with an enum isn't a bad idea after all...?

[oprypin]

And the big question that I keep insisting on...

• Should we assume that the "cmd" shell is the shell and deserves to be tied to a boolean shell: true

It might be cool to instead expand Process.run to accept an enum as the shell argument, which would then have implementations for sh, cmd, windows backed by corresponding quote implementations.

As for backticks, I don't have much hope of them ever doing anything sensible...