Indicate which APIs are annotated with the RequiresPreviewFeatures attribute

[jeffhandley]

With the introduction of the [RequiresPreviewFeatures] attribute, we should introduce a mechanism for ensuring that attribute shows up on APIs within the documentation. Each API annotated as such should point to a central documentation page discussing the implications of opting into preview features (and how to do so).

/cc @terrajobst

Originally posted by @tannergooding in dotnet/core#6417 (comment)

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[mimisasouvanh]

Internal item opened.

[terrajobst]

Any chance we can prioritize this in the .NET 8 timeframe?

The desire to use preview APIs across multiple products is growing. We might also highlight themAPIs in the VS experience as well but having a warning banner in the docs is still important.

[mimisasouvanh]

FYI @kexugit

[terrajobst]

@mimisasouvanh @gewarren @BillWagner

It looks like this was implemented for [RequiresPreviewFeatures]. Example. We should have a similar experience for [Experimental].

[mimisasouvanh]

@kexugit should I open a customer suggestion?

[gewarren]

I logged https://dev.azure.com/ceapex/Engineering/_workitems/edit/892618 for ExperimentalAttribute.