The new std.process does not use a mixed style.

Anyway, I am more worried about the use of `version (StdDoc)`. It is too easy to let the function signatures get out of sync with each other. I don't even like that public functions are separated into `version(Windows)`, etc. I think there should be only one declaration of public symbols, used on all all platforms. For small functions the `version`ing can be done within the function body, and for larger ones the public function can forward to platform-specific (and `version`ed) private implementation functions. Which reminds me, I should fix `std.process.pipe()` to not use this idiom.