compress/flate: update NewReader documentation
Calling close is no longer necessary.
It was was originally necessary to cleanup goroutines
spawned to decompress the stream.
This has not been the case since CL
4548079.
Update the documentation to mention how it handles trailing data
after the end of the DEFLATE stream.
Change-Id: Ieacba264230560713b7b8d604665223fd096f4ec
Reviewed-on: https://go-review.googlesource.com/c/go/+/430377
Run-TryBot: Joseph Tsai <joetsai@digital-static.net>
Auto-Submit: Joseph Tsai <joetsai@digital-static.net>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>