utf16le encoding is missed in the File System API doc for streams

[vsemozhetbyt]

There is an encoding list in the Buffer API doc: ascii, utf8, utf16le / ucs2, base64, binary, hex.

However the lists in the File System API doc for streams are not complete.

fs.createReadStream:

"The encoding can be 'utf8', 'ascii', or 'base64'."

fs.createWriteStream:

"The defaultEncoding can be 'utf8', 'ascii', binary, or 'base64'."

In the both lists the "utf16le / ucs2" encoding is misguidingly missed.

[claudiorodriguez]

As far as I can see at https://github.com/nodejs/node/blob/278a9267ec41f37e6b7dda876c417945d7725973/lib/_stream_readable.js and https://github.com/nodejs/node/blob/278a9267ec41f37e6b7dda876c417945d7725973/lib/_stream_writable.js - both fs.createReadStream and fs.createWriteStream internally use Buffer, so they should accept all of Buffer's encodings, unless I'm missing something. Maybe we could mention this and put a link to Buffer's doc in both cases?

[vsemozhetbyt]

At least my tests prove that the utf16le encoding works with fs.createReadStream and fs.createWriteStream.

[jasnell]

Fixed in master.