update documentation to include example of how to end stream

[markwbrown]

I'm not sure what JSSTYLED was supposed to be doing, but the close stream function has been commented out since #1a916f6ad7b1e731d1ea04ad4e44cc1db2cf4e94. In the absence of that getting changed, I think this documentation can help people with ending a stream. I found this useful in a node application to push its own logs over to s3.