Only post triple-quoted part into play.golang.org

[makarchuk]

Currently gopher posts the whole message which lead to playground entries much like this one https://play.golang.org/p/GzGXTenSHSJ.
Which doesn't help anybody

[theckman]

Would you mind re-raising this against https://github.com/gobridge/gopherbot for consideration? I'm going to be archiving this repo.