This was deceptive. It was always meant to be sort of a "GNU readline"
sort of thing where it provides a Command Line Interface to input text.
However that functionality did not exist and it was basically a red
herring for people trying to read line-delimited input from a stream.
In this commit the API is deleted, so that people can find the proper
API more easily.
A CLI text input abstraction would be useful but may not even need to be
in the standard library. As you can see in this commit, the guess_number
CLI game gets by just fine by using `std.fs.File.read`.
Thanks to the Windows Process Environment Block, it is possible to
obtain handles to the standard input, output, and error streams without
possibility of failure.
Andrew Kelley