Check Web APIs returning ActionResult with status code 2xx

Describe the problem you are trying to solve

ActionResult accepts a generic parameter but doesn't enforce strict-typing (related issue). But as what we have discussed here, it is ideal to improve the Analyzers instead of making the changes with the ControllerBase.

Describe suggestions on how to achieve the rule

I am literally new with Analyzers (like a few hours ago) but it would be awesome if we will be able to check the MethodDeclarationSyntax of a ReturnStatementSyntax to see if the content type of the returned OkObjectResult matches the identified generic parameter from the method itself (please do correct me if I'm wrong on what I have initially thought for the solution).

I suggest displaying red curly underlines to notify the developer of the mismatch.

Additional context

Even though I literally haven't tried making a single rule, I did a few moments ago but failed miserably (link to the repo - actual rule). Hence, went here to seek help.