Add windowsVerbatimArguments docs for child_process.spawn
This resurrects https://github.com/nodejs/node-v0.x-archive/pull/4259.
I changed a bit of the documentation to more closely mirror the docs found in the header http://docs.libuv.org/en/v1.x/process.html by taking the wording from https://nikhilm.github.io/uvbook/processes.html
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