Warn on missing attribute (NonAction)

[ErikWahlstrom]

InvalidOperationException: Action 'XXX (XXXProject)' does not have an attribute route. Action methods on controllers annotated with ApiControllerAttribute must be attribute routed.
Microsoft.AspNetCore.Mvc.ApplicationModels.ApiBehaviorApplicationModelProvider.EnsureActionIsAttributeRouted(ActionModel actionModel)
Microsoft.AspNetCore.Mvc.ApplicationModels.ApiBehaviorApplicationModelProvider.OnProvidersExecuting(ApplicationModelProviderContext context)
Microsoft.AspNetCore.Mvc.Internal.ControllerActionDescriptorProvider.BuildModel()
Microsoft.AspNetCore.Mvc.Internal.ControllerActionDescriptorProvider.GetDescriptors()
Microsoft.AspNetCore.Mvc.Internal.ControllerActionDescriptorProvider.OnProvidersExecuting(ActionDescriptorProviderContext context)
Microsoft.AspNetCore.Mvc.Infrastructure.DefaultActionDescriptorCollectionProvider.UpdateCollection()
Microsoft.AspNetCore.Mvc.Infrastructure.DefaultActionDescriptorCollectionProvider.Initialize()
Microsoft.AspNetCore.Mvc.Infrastructure.DefaultActionDescriptorCollectionProvider.get_ActionDescriptors()
Microsoft.AspNetCore.Mvc.Internal.AttributeRoute.GetTreeRouter()
Microsoft.AspNetCore.Mvc.Internal.AttributeRoute.RouteAsync(RouteContext context)
Microsoft.AspNetCore.Routing.RouteCollection.RouteAsync(RouteContext context)
Microsoft.AspNetCore.Builder.RouterMiddleware.Invoke(HttpContext httpContext)
Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)