Consider default to `--quiet` when using `--output-document=-` like Wget 1.x

I received a bug report in Fedora where the underlying issue was that Wget2 does not default to --quiet when "downloading" to stdin, which breaks piping documents in unpredictable ways.

I know this difference is documented in wget2(1), but would you please reconsider this behavior change? It would make adoption of Wget2 as a replacement for Wget1 a lot easier for people.