Document or fix io.EOF from watch API

[kklipsch]

While using the watch API it is possible to see a lot of io.EOF errors. It was not obvious to me that would be the case in the watch documentation. If this is expected the documentation should be more explicit about it.

[kklipsch]

Also, just to be clear, I'm happy to update the documentation but I don't want to do so if io.EOF shouldn't be happening.