Fixes#9219
@JunTaoLuo Dan calls out the implicit versioning "for 2.1 SDK or later;" however, we don't usually version the doc content by SDK release. We might need to say something for this update in the passage that I'm adding to the All topic (*aspnetcore/fundamentals/metapackage.md*) about which SDK version this applies to. I don't know if that's something that you would like to do or what version to call out.
I also remove the version from the samples. We also assume that devs are using the latest SDK with our samples.
Addresses #8579
I might be getting the hang of **_find and replace_** now. 😝
This doesn't touch a couple that ref 2.2.0. I'll tidy those up on https://github.com/aspnet/Docs/issues/8518 after 2.2 RTM.
Rick Anderson
Luke Latham