feat: Add Sink.none operator

[He-Pin]

Motivation:

refs: #1613
refs https://github.com/Kotlin/kotlinx.coroutines/releases/tag/1.10.0 too.

Result:

1. add Sink#none operator
2. The doc renders OK

[pjfanning]

it is not usually acceptable to add new features in a patch (in semver)

[He-Pin]

If there will be a 1.2.0 release, I suggest we delete some deprecated code and maybe drop Java 8 and Scala 2.12 too.

[He-Pin]

But if we only delivery features in minor release , that will slow us down
I agree that we should only delete things in minor release.

[raboof]

Seems like a nice utility.

I agree we shouldn't slow ourselves down.

In this case following semver strictly just means the 'since' tag should be 1.2.0 and the next release will be 1.2.0, right? That seems fine to me?

[pjfanning]

Seems like a nice utility.

I agree we shouldn't slow ourselves down.

In this case following semver strictly just means the 'since' tag should be 1.2.0 and the next release will be 1.2.0, right? That seems fine to me?

Having a 1.2.0 release does come with an overhead of adding extra testing in our other repos to test with 1.0, 1.1, 1.2 jars but it is achievable.

[He-Pin]

Maybe we can relax that, which means only removing things in the minor version, this way, we can move faster, otherwise , any contributor will wait a little longer to have their contributions released.