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.
* Added more details on remote validation to the MVC model validation page
* Described the attribute -> tag helper -> jquery unobtrusive validation -> jquery validate flow for client-side validation in a little more detail.
Removing \<OutputType> from updated 2.0 projects, as it's specified by
Sdk.Web, and we're (generally) not showing defaults in the files.
There's a chance that we'll need to make an additional update for
*wwwroot* to match the templates. I'm checking on that now.