Fixes#10264
[Review URL](https://review.docs.microsoft.com/en-us/aspnet/core/mvc/models/validation?view=aspnetcore-2.2&branch=pr-en-us-10390)
* Not too keen on "top-level node." It isn't documented anywhere, and Google Fu wasn't much help either. I've *guessed* from the API what it means (and I could be *wrong*).
* Side note: `Required` is *required* as a model property attribute to get client-side required validation to work AFAICT. Adding `Required` or `BindRequired` to the top-level node (parameter) doesn't make it work client-side. Not sure if that's an issue or not ... just a side behavior that I noticed when testing.
* `jQuery.validate()` doesn't seem to be a thing any longer. JS complains that it can't find the function with the most recent jQuery validation scripts (from the current templates). Everything seems to work without it, so I nixed it.
* The sample was *almost* updated for 2.2. This should take it across the finish line. 🏁
* In the OP, the dev said that they were missing `AddDataAnnotations`, but we don't doc that level of detail. If they go `AddMvcCore`, they're kind'a on their own to make sure that they have all of the bits in place.
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.
Rick Anderson
Luke Latham
Scott Addie
Henrik Røn
John Osborne
user135711
MelnikovIG
Dan Vicarel
Luke Latham
Scott Addie
Daniel Roth